Life events, locus of control, and behavioral problems among Chinese adolescents.

PubMed

Liu, X; Kurita, H; Uchiyama, M; Okawa, M; Liu, L; Ma, D

2000-12-01

This study examined associations of life events and locus of control with behavioral problems among 1,365 Chinese adolescents by using the Youth Self-Report (YSR), Adolescent Self-Rating Life Events Checklist (ASLEC), and the Nowicki-Strickland Locus of Control Scale for Children. Results indicated that the overall prevalence of behavioral and emotional problems was 10.7% (95% CI = 9.9-11.5%). Logistic-regression analyses showed that a total of 13 negative life events mainly coming from academic domain and interpersonal relationships, high life-stress score, and high external locus score significantly increased the risk for behavioral problems. Life stress and locus of control significantly interacted with behavioral problems. These findings support the linkage between stressful life events and psychopathology in a general population of adolescents from mainland China, and demonstrate the stress-moderating effects of locus of control on psychopathology as well.

Locus of Control and Sex Differences in Performance on an Instructional Task.

ERIC Educational Resources Information Center

Holloway, Richard L.; Robinson, Beatrice

1979-01-01

Used locus of control, ability, sex, task selection, task structure, and recall in a regression model to predict affective response to type of instruction of 104 high school seniors. Results showed a main effect for recall, and interaction effects for recall x sex and recall x ability. References are listed. (Author/JEG)

Does the perception that God controls health outcomes matter for health behaviors?

PubMed

Karvinen, Kristina H; Carr, Lucas J

2014-04-01

The purpose of this study was to examine the associations between God Locus of Health Control, health behaviors, and beliefs utilizing a cross-sectional online survey (N = 549). Results indicated that God Locus of Health Control was correlated with alcohol use, physical activity, perceived risk of chronic disease, and beliefs that poor health behaviors contribute to chronic disease (all p values < .05). Multiple regression analyses including covariates and other locus of control variables revealed that God Locus of Health Control was only an independent correlate of the belief that physical inactivity contributed to chronic disease. Insights from this study may be important for future faith-based health behavior change interventions.

THE BLANCO COSMOLOGY SURVEY: DATA ACQUISITION, PROCESSING, CALIBRATION, QUALITY DIAGNOSTICS, AND DATA RELEASE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Desai, S.; Mohr, J. J.; Semler, D. R.

2012-09-20

The Blanco Cosmology Survey (BCS) is a 60 night imaging survey of {approx}80 deg{sup 2} of the southern sky located in two fields: ({alpha}, {delta}) = (5 hr, -55 Degree-Sign ) and (23 hr, -55 Degree-Sign ). The survey was carried out between 2005 and 2008 in griz bands with the Mosaic2 imager on the Blanco 4 m telescope. The primary aim of the BCS survey is to provide the data required to optically confirm and measure photometric redshifts for Sunyaev-Zel'dovich effect selected galaxy clusters from the South Pole Telescope and the Atacama Cosmology Telescope. We process and calibrate themore » BCS data, carrying out point-spread function-corrected model-fitting photometry for all detected objects. The median 10{sigma} galaxy (point-source) depths over the survey in griz are approximately 23.3 (23.9), 23.4 (24.0), 23.0 (23.6), and 21.3 (22.1), respectively. The astrometric accuracy relative to the USNO-B survey is {approx}45 mas. We calibrate our absolute photometry using the stellar locus in grizJ bands, and thus our absolute photometric scale derives from the Two Micron All Sky Survey, which has {approx}2% accuracy. The scatter of stars about the stellar locus indicates a systematic floor in the relative stellar photometric scatter in griz that is {approx}1.9%, {approx}2.2%, {approx}2.7%, and {approx}2.7%, respectively. A simple cut in the AstrOmatic star-galaxy classifier spread{sub m}odel produces a star sample with good spatial uniformity. We use the resulting photometric catalogs to calibrate photometric redshifts for the survey and demonstrate scatter {delta}z/(1 + z) = 0.054 with an outlier fraction {eta} < 5% to z {approx} 1. We highlight some selected science results to date and provide a full description of the released data products.« less

The Blanco Cosmology Survey: Data Acquisition, Processing, Calibration, Quality Diagnostics and Data Release

DOE Office of Scientific and Technical Information (OSTI.GOV)

Desai, S.; /Munich U. /Munich, Tech. U., Universe; Armstrong, R.

2012-04-01

The Blanco Cosmology Survey (BCS) is a 60 night imaging survey of {approx}80 deg{sup 2} of the southern sky located in two fields: ({alpha},{delta})= (5 hr, -55{sup circ} and 23 hr, -55{sup circ}). The survey was carried out between 2005 and 2008 in griz bands with the Mosaic2 imager on the Blanco 4m telescope. The primary aim of the BCS survey is to provide the data required to optically confirm and measure photometric redshifts for Sunyaev-Zel'dovich effect selected galaxy clusters from the South Pole Telescope and the Atacama Cosmology Telescope. We process and calibrate the BCS data, carrying out PSFmore » corrected model fitting photometry for all detected objects. The median 10{sigma} galaxy (point source) depths over the survey in griz are approximately 23.3 (23.9), 23.4 (24.0), 23.0 (23.6) and 21.3 (22.1), respectively. The astrometric accuracy relative to the USNO-B survey is {approx}45 milli-arcsec. We calibrate our absolute photometry using the stellar locus in grizJ bands, and thus our absolute photometric scale derives from 2MASS which has {approx}2% accuracy. The scatter of stars about the stellar locus indicates a systematics floor in the relative stellar photometric scatter in griz that is {approx}1.9%, {approx}2.2%, {approx}2.7% and {approx}2.7%, respectively. A simple cut in the AstrOmatic star-galaxy classifier produces a star sample with good spatial uniformity. We use the resulting photometric catalogs to calibrate photometric redshifts for the survey and demonstrate scatter {delta} z/(1+z)=0.054 with an outlier fraction {eta}<5% to z{approx}1. We highlight some selected science results to date and provide a full description of the released data products.« less

Application of logistic regression to case-control association studies involving two causative loci.

PubMed

North, Bernard V; Curtis, David; Sham, Pak C

2005-01-01

Models in which two susceptibility loci jointly influence the risk of developing disease can be explored using logistic regression analysis. Comparison of likelihoods of models incorporating different sets of disease model parameters allows inferences to be drawn regarding the nature of the joint effect of the loci. We have simulated case-control samples generated assuming different two-locus models and then analysed them using logistic regression. We show that this method is practicable and that, for the models we have used, it can be expected to allow useful inferences to be drawn from sample sizes consisting of hundreds of subjects. Interactions between loci can be explored, but interactive effects do not exactly correspond with classical definitions of epistasis. We have particularly examined the issue of the extent to which it is helpful to utilise information from a previously identified locus when investigating a second, unknown locus. We show that for some models conditional analysis can have substantially greater power while for others unconditional analysis can be more powerful. Hence we conclude that in general both conditional and unconditional analyses should be performed when searching for additional loci.

Closed and open magnetic fields in stellar winds

NASA Technical Reports Server (NTRS)

Mullan, D. J.; Steinolfson, R. S.

1983-01-01

A numerical study of the interaction between a thermal wind and a global dipole field in the sun and in a giant star is reported. In order for closed field lines to persist near the equator (where a helmet-streamer-like configuration appears), the coronal temperature must be less than a critical value Tc, which scales as M/R. This condition is found to be equivalent to the following: for a static helmet streamer to persist, the sonic point above the helmet must not approach closer to the star than 2.2-2.6 stellar radii. Implications for rapid mass loss and X-ray emission from cool giants are pointed out. The results strengthen the case for identifying empirical dividing lines in the H-R diagram with a magnetic topology transition locus (MTTL). Support for the MTTL concept is also provided by considerations of the breakdown of magnetostatic equilibrium.

Blue Stragglers and Other Stars of Mass Consumption in Globular Clusters

NASA Astrophysics Data System (ADS)

Panurach, Teresa; Leigh, Nathan

2018-01-01

Simulations of globular clusters suggest that collisions between main-sequence (MS) stars happen frequently. Stellar evolution models show that these collision products can be photometrically identified, appearing off the MS locus. These collision products can appear brighter and bluer than the MS turnoff, called “blue stragglers,” or even less massive and redder than the MS. We use proper motion-cleaned photometry from the Hubble Space Telescope of 38 globular clusters to identify candidate collision products. We compare the spectral energy distributions of our candidates to theoretical templates for single and multiple star systems, to constrain the possible presence of a binary companion and test consistency with theoretical stellar evolution models for collision products. For the BSs, we also compare the observed velocities from the proper motion catalog along with mass estimates derived from isochrone-fitting to theoretical predictions for both the collision and binary mass transfer models and find better agreement with the former.

Cognitive functioning correlates of self-esteem and health locus of control in schizophrenia

PubMed Central

Wang, Chien-Shu; Wu, Jo Yung-Wei; Chang, Wei-Chung; Chuang, Shu-Ping

2013-01-01

Aim The study aimed to investigate the relationship among sociodemographic factors, neurocognitive factors, self-esteem, and health locus of control in patients diagnosed with schizophrenia. We examined the self-esteem, internal health locus of control, and external health locus of control through sociodemographic and neurocognitive factors. Methods Forty-six schizophrenic patients and 31 healthy residents from the community or hospital were recruited as the control group. All subjects participated in the self-esteem questionnaire, health locus of control questionnaire, and a series of neuropychological measures. Results Multiple regression analysis revealed that inhibition of attention and external health locus of control were predictors for self-esteem (r=−0.30, P<0.05; r=0.41, P<0.01); inhibition of attention and external health locus of control were contributors for internal health locus of control (r=−0.43, P<0.01; r=0.61, P<0.001); and education was related to external health locus of control (r=−0.31, P<0.05). Conclusion The current study integrated background characteristics and cognitive function to better understand the impact of self-esteem and health locus of control in schizophrenia. The findings indicated that inhibition of attention, external health locus of control, and education contributed to self-esteem, internal health locus of control and external health locus of control. However, the overall predicted variance accounted for by these predictors was small; thus, further research is necessary to examine imperative variables related with self-esteem and health locus of control in schizophrenia. PMID:24194641

Self concepts, health locus of control and cognitive functioning associated with health-promoting lifestyles in schizophrenia.

PubMed

Chuang, Shu Ping; Wu, Jo Yung Wei; Wang, Chien Shu; Liu, Chia Hsuan; Pan, Li Hsiang

2016-10-01

The study aimed to investigate the relationship among self concepts, health locus of control, cognitive functioning and health-promoting lifestyles in patients diagnosed with schizophrenia. We examined health-promoting lifestyles through self-efficacy, self-esteem, health locus of control and neurocognitive factors. Fifty-six people with schizophrenia were enrolled in the study group. All subjects participated in the self-esteem (Rosenberg Self-Esteem Scale), self-efficacy (General Self-Efficacy Scale), health locus of control (The Multidimensional Health Locus of Control Scales), health-promoting lifestyles (Health Promotion Life-style Profile-II) and a series of neurocognitive measures. Stepwise regression analysis revealed that self-efficacy, internal health locus of control and attentional set-shifting accounted for 42% of the variance in total health-promoting lifestyles scores. Self-efficacy, self-esteem, internal and powerful others health locus of control and attentional set-shifting were significant predictors for domains of health-promoting lifestyles, respectively. Study findings can help mental health professionals maintain and improve health-promoting behaviors through a better understanding of self-esteem, self-efficacy, health locus of control and neurocognitive functioning among people with schizophrenia. Copyright © 2016 Elsevier Inc. All rights reserved.

Theoretical gravity darkening as a function of optical depth. A first approach to fast rotating stars

NASA Astrophysics Data System (ADS)

Claret, A.

2016-04-01

Aims: Recent observations of very fast rotating stars show systematic deviations from the von Zeipel theorem and pose a challenge to the theory of gravity-darkening exponents (β1). In this paper, we present a new insight into the problem of temperature distribution over distorted stellar surfaces to try to reduce these discrepancies. Methods: We use a variant of the numerical method based on the triangles strategy, which we previously introduced, to evaluate the gravity-darkening exponents. The novelty of the present method is that the theoretical β1 is now computed as a function of the optical depth, that is, β1 ≡ β1(τ). The stellar evolutionary models, which are necessary to obtain the physical conditions of the stellar envelopes/atmospheres inherent to the numerical method, are computed via the code GRANADA. Results: When the resulting theoretical β1(τ) are compared with the best accurate data of very fast rotators, a good agreement for the six systems is simultaneously achieved. In addition, we derive an equation that relates the locus of constant convective efficiency in the Hertzsprung-Russell (HR) diagram with gravity-darkening exponents.

Recovering Galaxy Properties Using Gaussian Process SED Fitting

NASA Astrophysics Data System (ADS)

Iyer, Kartheik; Awan, Humna

2018-01-01

Information about physical quantities like the stellar mass, star formation rates, and ages for distant galaxies is contained in their spectral energy distributions (SEDs), obtained through photometric surveys like SDSS, CANDELS, LSST etc. However, noise in the photometric observations often is a problem, and using naive machine learning methods to estimate physical quantities can result in overfitting the noise, or converging on solutions that lie outside the physical regime of parameter space.We use Gaussian Process regression trained on a sample of SEDs corresponding to galaxies from a Semi-Analytic model (Somerville+15a) to estimate their stellar masses, and compare its performance to a variety of different methods, including simple linear regression, Random Forests, and k-Nearest Neighbours. We find that the Gaussian Process method is robust to noise and predicts not only stellar masses but also their uncertainties. The method is also robust in the cases where the distribution of the training data is not identical to the target data, which can be extremely useful when generalized to more subtle galaxy properties.

Dark Energy Survey Year 1 Results: The Photometric Data Set for Cosmology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drlica-Wagner, A.; Sevilla-Noarbe, I.; Rykoff, E. S.

In this paper, we describe the creation, content, and validation of the Dark Energy Survey (DES) internal year-one cosmology data set, Y1A1 GOLD, in support of upcoming cosmological analyses. The Y1A1 GOLD data set is assembled from multiple epochs of DES imaging and consists of calibrated photometric zero-points, object catalogs, and ancillary data products—e.g., maps of survey depth and observing conditions, star–galaxy classification, and photometric redshift estimates—that are necessary for accurate cosmological analyses. The Y1A1 GOLD wide-area object catalog consists ofmore » $$\\sim 137$$ million objects detected in co-added images covering $$\\sim 1800\\,{\\deg }^{2}$$ in the DES grizY filters. The 10σ limiting magnitude for galaxies is $g=23.4$, $r=23.2$, $i=22.5$, $z=21.8$, and $Y=20.1$. Photometric calibration of Y1A1 GOLD was performed by combining nightly zero-point solutions with stellar locus regression, and the absolute calibration accuracy is better than 2% over the survey area. Finally, DES Y1A1 GOLD is the largest photometric data set at the achieved depth to date, enabling precise measurements of cosmic acceleration at z ≲ 1.« less

Dark Energy Survey Year 1 Results: The Photometric Data Set for Cosmology

DOE PAGES

Drlica-Wagner, A.; Sevilla-Noarbe, I.; Rykoff, E. S.; ...

2018-04-03

In this paper, we describe the creation, content, and validation of the Dark Energy Survey (DES) internal year-one cosmology data set, Y1A1 GOLD, in support of upcoming cosmological analyses. The Y1A1 GOLD data set is assembled from multiple epochs of DES imaging and consists of calibrated photometric zero-points, object catalogs, and ancillary data products—e.g., maps of survey depth and observing conditions, star–galaxy classification, and photometric redshift estimates—that are necessary for accurate cosmological analyses. The Y1A1 GOLD wide-area object catalog consists ofmore » $$\\sim 137$$ million objects detected in co-added images covering $$\\sim 1800\\,{\\deg }^{2}$$ in the DES grizY filters. The 10σ limiting magnitude for galaxies is $g=23.4$, $r=23.2$, $i=22.5$, $z=21.8$, and $Y=20.1$. Photometric calibration of Y1A1 GOLD was performed by combining nightly zero-point solutions with stellar locus regression, and the absolute calibration accuracy is better than 2% over the survey area. Finally, DES Y1A1 GOLD is the largest photometric data set at the achieved depth to date, enabling precise measurements of cosmic acceleration at z ≲ 1.« less

Age differences in coping and locus of control: a study of managerial stress in Hong Kong.

PubMed

Siu, O; Cooper, C L; Spector, P E; Donald, I

2001-12-01

The present study involved data collection from 3 samples of Hong Kong managers to examine mechanisms by which age would relate to work well-being. A total of 634 managers was drawn by random sampling and purposive sampling methods. The results showed that age was positively related to well-being (job satisfaction and mental well-being). Furthermore, older managers reported fewer sources of stress, better coping, and a more internal locus of control. Multiple regression analyses suggested that the relations of age with 2 well-being indicators can be attributed to various combinations of coping, work locus of control, sources of stress, managerial level, and organizational tenure.

Patients suffering from restless legs syndrome have low internal locus of control and poor psychological functioning compared to healthy controls.

PubMed

Brand, Serge; Beck, Johannes; Hatzinger, Martin; Holsboer-Trachsler, Edith

2013-01-01

Restless legs syndrome (RLS) is a disturbing sensorimotor disorder negatively influencing both sleep and psychological functioning. The aim of the present study was to assess RLS patients with respect to locus of control, sleep-related personality traits, quality of life, and sleep as compared to healthy controls. Thirty-eight patients (18 females and 20 males; mean age: 56.06 years) diagnosed with RLS and an age- and gender-matched control group (n = 42) were recruited. Participants completed a series of questionnaires related to locus of control, personality traits, quality of life, and sleep. Compared to healthy controls, RLS patients had a lower internal locus of control, unfavourable sleep-related personality traits such as low self-confidence and higher mental arousal, poorer quality of life, and more depressive symptoms. Sleep was also affected. Multiple regression analyses showed that a low internal and a high external locus of control were predicted by RLS. The pattern of results suggests that RLS is associated with a low locus of control, negative personality traits, and poor quality of life as compared to healthy controls. Copyright © 2013 S. Karger AG, Basel.

Starspot variability as an X-ray radiation proxy

NASA Astrophysics Data System (ADS)

Arkhypov, Oleksiy V.; Khodachenko, Maxim L.; Lammer, Helmut; Güdel, Manuel; Lüftinger, Teresa; Johnstone, Colin P.

2018-05-01

Stellar X-ray emission plays an important role in the study of exoplanets as a proxy for stellar winds and as a basis for the prediction of extreme ultraviolet (EUV) flux, unavailable for direct measurements, which in their turn are important factors for the mass-loss of planetary atmospheres. Unfortunately, the detection thresholds limit the number of stars with the directly measured X-ray fluxes. At the same time, the known connection between the sunspots and X-ray sources allows using of the starspot variability as an accessible proxy for the stellar X-ray emission. To realize this approach, we analysed the light curves of 1729 main-sequence stars with rotation periods 0.5 < P < 30 d and effective temperatures 3236 < Teff < 7166 K observed by the Kepler mission. It was found that the squared amplitude of the first rotational harmonic of a stellar light curve may be used as a kind of activity index. This averaged index revealed practically the same relation with the Rossby number as that in the case of the X-ray to bolometric luminosity ratio Rx. As a result, the regressions for stellar X-ray luminosity Lx(P, Teff) and its related EUV analogue LEUV were obtained for the main-sequence stars. It was shown that these regressions allow prediction of average (over the considered stars) values of log (Lx) and log (LEUV) with typical errors of 0.26 and 0.22 dex, respectively. This, however, does not include the activity variations in particular stars related to their individual magnetic activity cycles.

CFHTLenS: co-evolution of galaxies and their dark matter haloes

NASA Astrophysics Data System (ADS)

Hudson, Michael J.; Gillis, Bryan R.; Coupon, Jean; Hildebrandt, Hendrik; Erben, Thomas; Heymans, Catherine; Hoekstra, Henk; Kitching, Thomas D.; Mellier, Yannick; Miller, Lance; Van Waerbeke, Ludovic; Bonnett, Christopher; Fu, Liping; Kuijken, Konrad; Rowe, Barnaby; Schrabback, Tim; Semboloni, Elisabetta; van Uitert, Edo; Velander, Malin

2015-02-01

Galaxy-galaxy weak lensing is a direct probe of the mean matter distribution around galaxies. The depth and sky coverage of the Canada-France-Hawaii Telescope Legacy Survey yield statistically significant galaxy halo mass measurements over a much wider range of stellar masses (108.75 to 1011.3 M⊙) and redshifts (0.2 < z < 0.8) than previous weak lensing studies. At redshift z ˜ 0.5, the stellar-to-halo mass ratio (SHMR) reaches a maximum of 4.0 ± 0.2 per cent as a function of halo mass at ˜1012.25 M⊙. We find, for the first time from weak lensing alone, evidence for significant evolution in the SHMR: the peak ratio falls as a function of cosmic time from 4.5 ± 0.3 per cent at z ˜ 0.7 to 3.4 ± 0.2 per cent at z ˜ 0.3, and shifts to lower stellar mass haloes. These evolutionary trends are dominated by red galaxies, and are consistent with a model in which the stellar mass above which star formation is quenched `downsizes' with cosmic time. In contrast, the SHMR of blue, star-forming galaxies is well fitted by a power law that does not evolve with time. This suggests that blue galaxies form stars at a rate that is balanced with their dark matter accretion in such a way that they evolve along the SHMR locus. The redshift dependence of the SHMR can be used to constrain the evolution of the galaxy population over cosmic time.

Application of Multi-task Lasso Regression in the Stellar Parametrization

NASA Astrophysics Data System (ADS)

Chang, L. N.; Zhang, P. A.

2015-01-01

The multi-task learning approaches have attracted the increasing attention in the fields of machine learning, computer vision, and artificial intelligence. By utilizing the correlations in tasks, learning multiple related tasks simultaneously is better than learning each task independently. An efficient multi-task Lasso (Least Absolute Shrinkage Selection and Operator) regression algorithm is proposed in this paper to estimate the physical parameters of stellar spectra. It not only makes different physical parameters share the common features, but also can effectively preserve their own peculiar features. Experiments were done based on the ELODIE data simulated with the stellar atmospheric simulation model, and on the SDSS data released by the American large survey Sloan. The precision of the model is better than those of the methods in the related literature, especially for the acceleration of gravity (lg g) and the chemical abundance ([Fe/H]). In the experiments, we changed the resolution of the spectrum, and applied the noises with different signal-to-noise ratio (SNR) to the spectrum, so as to illustrate the stability of the model. The results show that the model is influenced by both the resolution and the noise. But the influence of the noise is larger than that of the resolution. In general, the multi-task Lasso regression algorithm is easy to operate, has a strong stability, and also can improve the overall accuracy of the model.

Perceived academic performance, self-esteem and locus of control as indicators of need for assessment of adolescent suicide risk: implications for teachers.

PubMed

Martin, Graham; Richardson, Angela S; Bergen, Helen A; Roeger, Leigh; Allison, Stephen

2005-02-01

There is currently a need for research into indicators that could be used by non-clinical professionals working with young people, to inform the need for referral for further clinical assessment of those at risk of suicide. Participants of this repeated measures longitudinal study, were 2603, 2485, and 2246 school students aged 13, 14, and 15, respectively, from 27 South Australian Schools. Perceived academic performance, self-esteem and locus of control are significantly associated with suicidality. Further, logistic regression of longitudinal results suggests that perceived academic performance, over and above self-esteem and locus of control, in some instances, is a good long-term predictor of suicidality.

[Atmospheric parameter estimation for LAMOST/GUOSHOUJING spectra].

PubMed

Lu, Yu; Li, Xiang-Ru; Yang, Tan

2014-11-01

It is a key task to estimate the atmospheric parameters from the observed stellar spectra in exploring the nature of stars and universe. With our Large Sky Area Multi-Object Fiber Spectroscopy Telescope (LAMOST) which begun its formal Sky Survey in September 2012, we are obtaining a mass of stellar spectra in an unprecedented speed. It has brought a new opportunity and a challenge for the research of galaxies. Due to the complexity of the observing system, the noise in the spectrum is relatively large. At the same time, the preprocessing procedures of spectrum are also not ideal, such as the wavelength calibration and the flow calibration. Therefore, there is a slight distortion of the spectrum. They result in the high difficulty of estimating the atmospheric parameters for the measured stellar spectra. It is one of the important issues to estimate the atmospheric parameters for the massive stellar spectra of LAMOST. The key of this study is how to eliminate noise and improve the accuracy and robustness of estimating the atmospheric parameters for the measured stellar spectra. We propose a regression model for estimating the atmospheric parameters of LAMOST stellar(SVM(lasso)). The basic idea of this model is: First, we use the Haar wavelet to filter spectrum, suppress the adverse effects of the spectral noise and retain the most discrimination information of spectrum. Secondly, We use the lasso algorithm for feature selection and extract the features of strongly correlating with the atmospheric parameters. Finally, the features are input to the support vector regression model for estimating the parameters. Because the model has better tolerance to the slight distortion and the noise of the spectrum, the accuracy of the measurement is improved. To evaluate the feasibility of the above scheme, we conduct experiments extensively on the 33 963 pilot surveys spectrums by LAMOST. The accuracy of three atmospheric parameters is log Teff: 0.006 8 dex, log g: 0.155 1 dex, [Fe/H]: 0.104 0 dex.

Kepler AutoRegressive Planet Search

NASA Astrophysics Data System (ADS)

Feigelson, Eric

NASA's Kepler mission is the source of more exoplanets than any other instrument, but the discovery depends on complex statistical analysis procedures embedded in the Kepler pipeline. A particular challenge is mitigating irregular stellar variability without loss of sensitivity to faint periodic planetary transits. This proposal presents a two-stage alternative analysis procedure. First, parametric autoregressive ARFIMA models, commonly used in econometrics, remove most of the stellar variations. Second, a novel matched filter is used to create a periodogram from which transit-like periodicities are identified. This analysis procedure, the Kepler AutoRegressive Planet Search (KARPS), is confirming most of the Kepler Objects of Interest and is expected to identify additional planetary candidates. The proposed research will complete application of the KARPS methodology to the prime Kepler mission light curves of 200,000: stars, and compare the results with Kepler Objects of Interest obtained with the Kepler pipeline. We will then conduct a variety of astronomical studies based on the KARPS results. Important subsamples will be extracted including Habitable Zone planets, hot super-Earths, grazing-transit hot Jupiters, and multi-planet systems. Groundbased spectroscopy of poorly studied candidates will be performed to better characterize the host stars. Studies of stellar variability will then be pursued based on KARPS analysis. The autocorrelation function and nonstationarity measures will be used to identify spotted stars at different stages of autoregressive modeling. Periodic variables with folded light curves inconsistent with planetary transits will be identified; they may be eclipsing or mutually-illuminating binary star systems. Classification of stellar variables with KARPS-derived statistical properties will be attempted. KARPS procedures will then be applied to archived K2 data to identify planetary transits and characterize stellar variability.

A Method to Measure the Transverse Magnetic Field and Orient the Rotational Axis of Stars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leone, Francesco; Scalia, Cesare; Gangi, Manuele

Direct measurements of stellar magnetic fields are based on the splitting of spectral lines into polarized Zeeman components. With a few exceptions, Zeeman signatures are hidden in data noise, and a number of methods have been developed to measure the average, over the visible stellar disk, of longitudinal components of the magnetic field. At present, faint stars are only observable via low-resolution spectropolarimetry, which is a method based on the regression of the Stokes V signal against the first derivative of Stokes I . Here, we present an extension of this method to obtain a direct measurement of the transversemore » component of stellar magnetic fields by the regression of high-resolution Stokes Q and U as a function of the second derivative of Stokes I . We also show that it is possible to determine the orientation in the sky of the rotation axis of a star on the basis of the periodic variability of the transverse component due to its rotation. The method is applied to data, obtained with the Catania Astrophysical Observatory Spectropolarimeter along the rotational period of the well known magnetic star β CrB.« less

Application of Multi-task Lasso Regression in the Parametrization of Stellar Spectra

NASA Astrophysics Data System (ADS)

Chang, Li-Na; Zhang, Pei-Ai

2015-07-01

The multi-task learning approaches have attracted the increasing attention in the fields of machine learning, computer vision, and artificial intelligence. By utilizing the correlations in tasks, learning multiple related tasks simultaneously is better than learning each task independently. An efficient multi-task Lasso (Least Absolute Shrinkage Selection and Operator) regression algorithm is proposed in this paper to estimate the physical parameters of stellar spectra. It not only can obtain the information about the common features of the different physical parameters, but also can preserve effectively their own peculiar features. Experiments were done based on the ELODIE synthetic spectral data simulated with the stellar atmospheric model, and on the SDSS data released by the American large-scale survey Sloan. The estimation precision of our model is better than those of the methods in the related literature, especially for the estimates of the gravitational acceleration (lg g) and the chemical abundance ([Fe/H]). In the experiments we changed the spectral resolution, and applied the noises with different signal-to-noise ratios (SNRs) to the spectral data, so as to illustrate the stability of the model. The results show that the model is influenced by both the resolution and the noise. But the influence of the noise is larger than that of the resolution. In general, the multi-task Lasso regression algorithm is easy to operate, it has a strong stability, and can also improve the overall prediction accuracy of the model.

Predicting parenting stress in caregivers of children with brain tumours.

PubMed

Bennett, Emily; English, Martin William; Rennoldson, Michael; Starza-Smith, Arleta

2013-03-01

The purpose of the study was to identify factors that contribute to parenting stress in caregivers of children diagnosed with brain tumours. The study was cross-sectional and recruited 37 participants from a clinical database at a specialist children's hospital. Parents were sent questionnaires, which were used to measure factors related to stress in caregivers of children diagnosed with a brain tumour. Stress levels were measured using the Parenting Stress Index-Short Form (PSI/SF). Correlation analysis and multiple linear regression were used to examine the associations between parenting stress and coping styles, locus of control, parent-perceived child disability and time since diagnosis. Results revealed that 51% of parents were experiencing clinically significant levels of stress. The mean stress level of parents in the study was significantly higher than the PSI/SF norms (t = 4.7, p < .001). Regression analysis revealed that external locus of control and coping by accepting responsibility accounted for 67% of the variance in parenting stress. Other styles of coping, child behaviour problems and the amount of time since diagnosis were not found to be predictive of levels of parenting stress. There was a high prevalence of parenting stress in caregivers of children with a brain tumour. An external locus of control and coping by accepting responsibility increased the likelihood of elevated levels of stress. Results emphasised the importance of ongoing support for parents of children with brain tumours. Intervention might helpfully be centred on strategies to increase parents' internal locus of control. Copyright © 2012 John Wiley & Sons, Ltd.

Attitudes Toward Obese Persons and Weight Locus of Control in Chinese Nurses: A Cross-sectional Survey.

PubMed

Wang, Yan; Ding, Ye; Song, Daoping; Zhu, Daqiao; Wang, Jianrong

2016-01-01

Obese individuals frequently experience weight-related bias or discrimination-even in healthcare settings. Although obesity bias has been associated with several demographic factors, little is known about the association of weight locus of control with bias against overweight persons or about weight bias among Chinese health professionals. The aim of the study was to examine attitudes toward obese patients in a sample of Chinese registered nurses (RNs) and the relationship between weight bias and nurses' weight locus of control. RNs working in nine community health service centers across Shanghai, China, answered three self-report questionnaires: The Attitudes Toward Obese Persons Scale (ATOP), the External Weight Locus of Control Subscale (eWLOC) from the Dieting Belief Scale, and a sociodemographic profile. Hierarchical, stepwise, multiple regression was used to predict ATOP scores. From among 385 invited, a total of 297 RNs took part in the study (77.1% response rate). Participants scored an average of 71.04 on the ATOP, indicating slightly positive attitudes toward obese persons, and 30.08 on the eWLOC, indicating a belief in the uncontrollability of body weight. Using hierarchical, stepwise, multiple regression, two predictors of ATOP scores were statistically significant (eWLOC scores and status as a specialist rather than generalist nurse), but explained variance was low. Chinese RNs seemed to have relatively neutral or even slightly positive attitudes toward obese persons. Those nurses who believed that obesity was beyond the individual's control or worked in specialties were more likely to have positive attitudes toward obese people. Improved understanding of the comprehensive etiology of obesity is needed.

Stellar Color Regression: A Spectroscopy-based Method for Color Calibration to a Few Millimagnitude Accuracy and the Recalibration of Stripe 82

NASA Astrophysics Data System (ADS)

Yuan, Haibo; Liu, Xiaowei; Xiang, Maosheng; Huang, Yang; Zhang, Huihua; Chen, Bingqiu

2015-02-01

In this paper we propose a spectroscopy-based stellar color regression (SCR) method to perform accurate color calibration for modern imaging surveys, taking advantage of millions of stellar spectra now available. The method is straightforward, insensitive to systematic errors in the spectroscopically determined stellar atmospheric parameters, applicable to regions that are effectively covered by spectroscopic surveys, and capable of delivering an accuracy of a few millimagnitudes for color calibration. As an illustration, we have applied the method to the Sloan Digital Sky Survey (SDSS) Stripe 82 data. With a total number of 23,759 spectroscopically targeted stars, we have mapped out the small but strongly correlated color zero-point errors present in the photometric catalog of Stripe 82, and we improve the color calibration by a factor of two to three. Our study also reveals some small but significant magnitude dependence errors in the z band for some charge-coupled devices (CCDs). Such errors are likely to be present in all the SDSS photometric data. Our results are compared with those from a completely independent test based on the intrinsic colors of red galaxies presented by Ivezić et al. The comparison, as well as other tests, shows that the SCR method has achieved a color calibration internally consistent at a level of about 5 mmag in u - g, 3 mmag in g - r, and 2 mmag in r - i and i - z. Given the power of the SCR method, we discuss briefly the potential benefits by applying the method to existing, ongoing, and upcoming imaging surveys.

Work stress and depression among direct support professionals: the role of work support and locus of control.

PubMed

Gray-Stanley, J A; Muramatsu, N; Heller, T; Hughes, S; Johnson, T P; Ramirez-Valles, J

2010-08-01

Although work stress can impede the capacity of direct support professionals and contribute to mental health challenges, external (i.e. work social support) and internal resources (i.e. an internal locus of control) have been shown to help DSPs cope more actively. We examined how work stress was associated with depression, with a particular focus on the role of resources. Direct support professionals (n = 323) who serve adults with intellectual and developmental disabilities from five community-based organisations completed a cross-sectional, self-administered survey which measured work stress, work support, locus of control, and depression. Multiple regression analyses demonstrated that work stress was positively associated with depression, while resources were negatively associated with depression. In particular, work support moderated the effects of client disability stress, supervisory support lessened the effects of role conflict, and locus of control moderated the effects of workload. Such findings suggest the importance of external and internal resources for staff mental health. This research underscores the need for strong work social support systems and interventions to help staff manage work stressors.

Work stress and depression among direct support professionals: the role of work support and locus of control

PubMed Central

Gray-Stanley, J. A.; Muramatsu, N.; Heller, T.; Hughes, S.; Johnson, T. P.; Ramirez-Valles, J.

2013-01-01

Background Although work stress can impede the capacity of direct support professionals and contribute to mental health challenges, external (i.e. work social support) and internal resources (i.e. an internal locus of control) have been shown to help DSPs cope more actively. We examined how work stress was associated with depression, with a particular focus on the role of resources. Method Direct support professionals (n = 323) who serve adults with intellectual and developmental disabilities from five community-based organisations completed a cross-sectional, self-administered survey which measured work stress, work support, locus of control, and depression. Results Multiple regression analyses demonstrated that work stress was positively associated with depression, while resources were negatively associated with depression. In particular, work support moderated the effects of client disability stress, supervisory support lessened the effects of role conflict, and locus of control moderated the effects of workload. Conclusions Such findings suggest the importance of external and internal resources for staff mental health. This research underscores the need for strong work social support systems and interventions to help staff manage work stressors. PMID:20633203

Internal predictors of burnout in psychiatric nurses: An Indian study

PubMed Central

Chakraborty, Rudraprosad; Chatterjee, Arunima; Chaudhury, Suprakash

2012-01-01

Background: Research has not adequately focused on the issue of burnout in Psychiatric nurses, despite the fact that they suffer considerable stress in their work. Till date no study has been conducted on burnout among psychiatric nurses in India. Further, there is a particular lack of research in internal variables predicting burnout in them. Aims: To determine whether there are any internal psychological factors relevant to burnout in psychiatric nurses in India. Materials and Methods: We recruited 101 psychiatric nurses scoring less than two in General Health Questionnaire, version 12 (GHQ-12) from two psychiatric hospitals after obtaining informed consent. All subjects filled up a sociodemographic data sheet along with global adjustment scale, emotional maturity scale, PGI general well-being scale, locus of control scale, and Copenhagen burnout inventory (CBI). Correlations between burnout and sociodemographic/clinical variables were done by Pearson's r or Spearman's rho. Signi ficant variables were entered in a stepwise multiple linear regression analysis with total burnout score as dependent variable. Results: Age, duration of total period of nursing, prior military training, locus of control, sense of general well-being, adjustment capabilities, and emotional maturity had significant relation with burnout. Of them, emotional maturity was the most significant protective factors against burnout along with adjustment capabilities, sense of physical well-being, and military training in decreasing significance. Together they explained 41% variation in total burnout score which is significant at <0.001 level. An internal locus of control was inversely correlated with burnout, but failed to predict it in regression analysis. Conclusion: Emotional maturity, adjustability, sense of general physical well-being as well as prior military training significantly predicted lower burnout. Of them, emotional maturity was the most important predictor. Internal locus of control was also correlated with lower burnout. PMID:24250044

Internal predictors of burnout in psychiatric nurses: An Indian study.

PubMed

Chakraborty, Rudraprosad; Chatterjee, Arunima; Chaudhury, Suprakash

2012-07-01

Research has not adequately focused on the issue of burnout in Psychiatric nurses, despite the fact that they suffer considerable stress in their work. Till date no study has been conducted on burnout among psychiatric nurses in India. Further, there is a particular lack of research in internal variables predicting burnout in them. To determine whether there are any internal psychological factors relevant to burnout in psychiatric nurses in India. We recruited 101 psychiatric nurses scoring less than two in General Health Questionnaire, version 12 (GHQ-12) from two psychiatric hospitals after obtaining informed consent. All subjects filled up a sociodemographic data sheet along with global adjustment scale, emotional maturity scale, PGI general well-being scale, locus of control scale, and Copenhagen burnout inventory (CBI). Correlations between burnout and sociodemographic/clinical variables were done by Pearson's r or Spearman's rho. Signi ficant variables were entered in a stepwise multiple linear regression analysis with total burnout score as dependent variable. Age, duration of total period of nursing, prior military training, locus of control, sense of general well-being, adjustment capabilities, and emotional maturity had significant relation with burnout. Of them, emotional maturity was the most significant protective factors against burnout along with adjustment capabilities, sense of physical well-being, and military training in decreasing significance. Together they explained 41% variation in total burnout score which is significant at <0.001 level. An internal locus of control was inversely correlated with burnout, but failed to predict it in regression analysis. Emotional maturity, adjustability, sense of general physical well-being as well as prior military training significantly predicted lower burnout. Of them, emotional maturity was the most important predictor. Internal locus of control was also correlated with lower burnout.

Physical health, self-reliance, and emotional control as moderators of the relationship between locus of control and mental health among men treated for prostate cancer.

PubMed

Burns, Shaun Michael; Mahalik, James R

2006-12-01

This investigation examined the moderating effects of physical health and scripts for masculinity (i.e., self-reliance and emotional control) on the relationship between powerful other people locus of control and mental health for 230 men treated for prostate cancer. Regression analyses indicated that physical health and masculine gender scripts moderated the association between powerful other people locus of control and mental health. Specifically, men with poor physical health evinced negative mental health when they endorsed masculine gender scripts and believed powerful other people (i.e., family, friends, or peers) were influential in controlling their cancer. By comparison, men reporting poor physical health, strong beliefs that powerful other people controlled their cancer, and less adherence to masculine scripts experienced positive mental health. The authors discuss future research directions and potential mental health implications for men treated for prostate cancer.

Material Hardship and Internal Locus of Control Over the Prevention of Child Obesity in Low-Income Hispanic Pregnant Women.

PubMed

Gross, Rachel S; Mendelsohn, Alan L; Gross, Michelle B; Scheinmann, Roberta; Messito, Mary Jo

2016-07-01

To determine the relations between household material hardships and having a low internal locus of control over the prevention of child obesity in low-income Hispanic pregnant women. We performed a cross-sectional analysis of baseline data collected during a third trimester prenatal visit from women participating in the Starting Early Study, a randomized controlled trial to test the efficacy of a primary care-based family-centered early child obesity prevention intervention. Using multiple logistic regression analyses, we determined whether 4 domains of material hardship (food insecurity, difficulty paying bills, housing disrepair, neighborhood stress), considered individually and also cumulatively, were associated with having a low internal locus of control over the prevention of child obesity. The sample included 559 low-income Hispanic pregnant women, with 60% having experienced at least 1 hardship. Food insecurity was independently associated with a low internal locus of control over the prevention of child obesity (adjusted odds ratio, 2.38; 95% confidence interval, 1.50-3.77), controlling for other hardships and confounders. Experiencing a greater number of material hardships was associated in a dose-dependent relationship with an increased odds of having a low internal locus of control. Prenatal material hardships, in particular food insecurity, were associated with having a lower prenatal internal locus of control over the prevention of child obesity. Longitudinal follow-up of this cohort is needed to determine how relations between material hardships and having a low internal locus of control will ultimately affect infant feeding practices and child weight trajectories. Copyright © 2016 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

STELLAR COLOR REGRESSION: A SPECTROSCOPY-BASED METHOD FOR COLOR CALIBRATION TO A FEW MILLIMAGNITUDE ACCURACY AND THE RECALIBRATION OF STRIPE 82

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yuan, Haibo; Liu, Xiaowei; Xiang, Maosheng

In this paper we propose a spectroscopy-based stellar color regression (SCR) method to perform accurate color calibration for modern imaging surveys, taking advantage of millions of stellar spectra now available. The method is straightforward, insensitive to systematic errors in the spectroscopically determined stellar atmospheric parameters, applicable to regions that are effectively covered by spectroscopic surveys, and capable of delivering an accuracy of a few millimagnitudes for color calibration. As an illustration, we have applied the method to the Sloan Digital Sky Survey (SDSS) Stripe 82 data. With a total number of 23,759 spectroscopically targeted stars, we have mapped out the smallmore » but strongly correlated color zero-point errors present in the photometric catalog of Stripe 82, and we improve the color calibration by a factor of two to three. Our study also reveals some small but significant magnitude dependence errors in the z band for some charge-coupled devices (CCDs). Such errors are likely to be present in all the SDSS photometric data. Our results are compared with those from a completely independent test based on the intrinsic colors of red galaxies presented by Ivezić et al. The comparison, as well as other tests, shows that the SCR method has achieved a color calibration internally consistent at a level of about 5 mmag in u – g, 3 mmag in g – r, and 2 mmag in r – i and i – z. Given the power of the SCR method, we discuss briefly the potential benefits by applying the method to existing, ongoing, and upcoming imaging surveys.« less

Stellar Populations of over 1000 z ∼ 0.8 Galaxies from LEGA-C: Ages and Star Formation Histories from D n 4000 and Hδ

NASA Astrophysics Data System (ADS)

Wu, Po-Feng; van der Wel, Arjen; Gallazzi, Anna; Bezanson, Rachel; Pacifici, Camilla; Straatman, Caroline; Franx, Marijn; Barišić, Ivana; Bell, Eric F.; Brammer, Gabriel B.; Calhau, Joao; Chauke, Priscilla; van Houdt, Josha; Maseda, Michael V.; Muzzin, Adam; Rix, Hans-Walter; Sobral, David; Spilker, Justin; van de Sande, Jesse; van Dokkum, Pieter; Wild, Vivienne

2018-03-01

Drawing from the LEGA-C data set, we present the spectroscopic view of the stellar population across a large volume- and mass-selected sample of galaxies at large look-back time. We measure the 4000 Å break (D n 4000) and Balmer absorption line strengths (probed by Hδ) from 1019 high-quality spectra of z = 0.6–1.0 galaxies with M * = 2 × 1010 M ⊙ to 3 × 1011 M ⊙. Our analysis serves as a first illustration of the power of high-resolution, high signal-to-noise ratio continuum spectroscopy at intermediate redshifts as a qualitatively new tool to constrain galaxy formation models. The observed D n 4000–EW(Hδ) distribution of our sample overlaps with the distribution traced by present-day galaxies, but z ∼ 0.8 galaxies populate that locus in a fundamentally different manner. While old galaxies dominate the present-day population at all stellar masses >2 × 1010 M ⊙, we see a bimodal D n 4000–EW(Hδ) distribution at z ∼ 0.8, implying a bimodal light-weighted age distribution. The light-weighted age depends strongly on stellar mass, with the most massive galaxies >1 × 1011 M ⊙ being almost all older than 2 Gyr. At the same time, we estimate that galaxies in this high-mass range are only ∼3 Gyr younger than their z ∼ 0.1 counterparts, at odds with purely passive evolution given a difference in look-back time of >5 Gyr; younger galaxies must grow to >1011 M ⊙ in the meantime, or small amounts of young stars must keep the light-weighted ages young. Star-forming galaxies at z ∼ 0.8 have stronger Hδ absorption than present-day galaxies with the same D n 4000, implying larger short-term variations in star formation activity.

The MOSDEF Survey: Direct Observational Constraints on the Ionizing Photon Production Efficiency, ξ ion, at z ∼ 2

NASA Astrophysics Data System (ADS)

Shivaei, Irene; Reddy, Naveen A.; Siana, Brian; Shapley, Alice E.; Kriek, Mariska; Mobasher, Bahram; Freeman, William R.; Sanders, Ryan L.; Coil, Alison L.; Price, Sedona H.; Fetherolf, Tara; Azadi, Mojegan; Leung, Gene; Zick, Tom

2018-03-01

We combine Hα and Hβ spectroscopic measurements and UV photometry for a sample of 673 galaxies from the MOSDEF survey to constrain hydrogen-ionizing photon production efficiencies ({ξ }ion}) at z = 1.4–2.6. We find < {log}({ξ }ion}/[{{{s}}}-1/{erg} {{{s}}}-1 {Hz}}-1])> = 25.06 (25.34), assuming the Calzetti (SMC) curve for the UV dust correction and a scatter of 0.28 dex in the {ξ }ion} distribution. After accounting for observational uncertainties and variations in dust attenuation, we conclude that the remaining scatter in {ξ }ion} is likely dominated by galaxy-to-galaxy variations in stellar populations, including the slope and upper-mass cutoff of the initial mass function, stellar metallicity, star formation burstiness, and stellar evolution (e.g., single/binary star evolution). Moreover, {ξ }ion} is elevated in galaxies with high ionization states (high [O III]/[O II]) and low oxygen abundances (low [N II]/Hα and high [O III]/Hβ) in the ionized ISM. However, {ξ }ion} does not correlate with the offset from the z ∼ 0 star-forming locus in the BPT diagram, suggesting no change in the hardness of the ionizing radiation accompanying the offset from the z ∼ 0 sequence. We also find that galaxies with blue UV spectral slopes (< β > =-2.1) have {ξ }ion} elevated by a factor of ∼2 relative to the average {ξ }ion} of the sample (< β > =-1.4). If these blue galaxies are similar to those at z > 6, our results suggest that a lower Lyman-continuum escape fraction is required for galaxies to maintain reionization, compared to the canonical {ξ }ion} predictions from stellar population models. Furthermore, we demonstrate that even with robustly dust-corrected Hα, the UV dust attenuation can cause on average a ∼0.3 dex systematic uncertainty in {ξ }ion} calculations.

The efficacy of a modified Theory of Reasoned Action to explain gambling behavior in college students.

PubMed

Thrasher, Robert G; Andrew, Damon P S; Mahony, Daniel F

2011-09-01

Recently, Thrasher et al. (College Student Affairs Journal 27(1): 57-75, 2007) explored the efficacy of the Theory of Reasoned Action (TRA; Ajzen and Fishbein, Attitudes, personality, and behavior, 1980) in explaining gambling behavior of college students. However, their study found the TRA only predicted small amounts of variance in gambling intentions. Heeding their call to enhance the efficacy of the TRA through the addition of explanatory variables to the model, the present study incorporated gambling motivations and locus of control as moderating variables within the TRA to test the potential of a modified TRA in explaining gambling behavior of college students. A total of 345 students at a major metropolitan research university in the Midwest volunteered to participate in the study. A series of hierarchical linear regressions indicated intrinsic motivation to accomplish (p = .002) significantly moderated the relationship between gambling attitudes and gambling intentions. Further, internal locus of control (p < .001), chance locus of control (p < .001), and powerful others locus of control (p < .001) also significantly moderated the relationship between gambling attitudes and gambling intentions. The significant impact of the moderating variables on the relationship between gambling attitudes and intentions suggests intrinsic motivation and locus of control can alter the impact of the relationship between gambling attitudes and gambling intentions.

[Self-esteem, resilience, locus of control and suicide risk in nursing students].

PubMed

Montes-Hidalgo, Javier; Tomás-Sábado, Joaquín

2016-01-01

Assuming that suicide is the result of a series of factors acting cumulatively, the aim of this paper was to study the association of self-esteem, resilience and locus of control with the risk of suicidal behavior in a sample of nursing students. Observational, cross-sectional and correlational study with 186 nursing students who answered a questionnaire that contained, in addition to demographic data, the Spanish forms of Rosenberg self-esteem scale, the brief resilient coping scale, the Plutchik scale of suicide risk and the Rotter's internal-external locus of control scale. The scores of males and females are very similar on all scales except Locus of Control, where a significantly greater tendency of females attributed to external control. 6.4% of students have scores indicating suicide risk. Suicide risk scores correlated negatively and significantly with self-esteem and resilience and positively with locus of control. The multiple linear regression analysis identified self-esteem as the main variable related to suicide risk. The results suggest that students who have low self-esteem, have difficulty in adjusting to adverse situations and tend to the external attribution of the consequences of their actions may have an increased risk of suicidal behavior. Furthermore, the identification of self-esteem as the important factor involved in suicide risk can help in designing prevention programs. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

Psychosocial work conditions, unemployment and health locus of control: a population-based study.

PubMed

Sadiq Mohammad Ali; Lindström, Martin

2008-06-01

To investigate the association between psychosocial work conditions, unemployment and lack of belief in the possibility of influencing one's own health. The 2000 public health survey in Scania is a cross-sectional postal questionnaire study with a 59% participation rate. In total, 5180 persons aged 18-64 years who belonged to the workforce and the unemployed were included in this study. Logistic regression models were used to investigate the associations between psychosocial factors at work and unemployment, and lack of belief in the possibility of influencing one's own health (external locus of control). Psychosocial conditions at work were defined according to the Karasek-Theorell demand-control/decision latitudes into relaxed, active, passive, and job strain categories. The multivariate analyses included age, country of birth, education, economic stress, and social participation. In total, 26.6% of all men and 26.9% of all women lack an internal locus of control. The passive, job strain and unemployed categories have significantly higher odds ratios of lack of internal locus of control, as compared to the relaxed reference category. No such significant differences are observed for the active category. These patterns remain in the multivariate models, with the exception of the passive and unemployed categories among men, in which the significant differences disappear. Psychosocial work conditions and unemployment may affect health locus of control. The control dimension in the Karasek-Theorell model seems to be of greatest importance.

[The significance of the relationship between external/internal locus of control and adolescent substance use in behavioral medicine].

PubMed

Pikó, Bettina; Kovács, Eszter; Kriston, Pálma

2011-02-27

Prevention and treatment of the addictions are key public health priorities in modern society. In medical practice, in relation to the biochemical processes, mapping the addiction-prone personality traits, like external/internal locus of control are getting more and more attention. Individuals with high level on internal locus of control, for example, tend to take care of their health behavior; the lack of it, on the other hand, may worsen the effectiveness of stress release which may increase the likelihood of turning to substance use. The main goal of the present study was to investigate the relationship between adolescent substance use (both lifetime prevalence and the actual substance user status) and external/internal locus of control). The data collection of the questionnaire survey was going on among 656 high school students in Szeged (age range between 14-21 years, mean = 16.5 years, S.D. = 1.5 years of age, 49.1% of the sample was female). Associations between indicators of substance use (as dependent variables) and scale points of external/internal locus of control (as independent variables) were assessed using odds ratios calculated by logistic regression analyses, whereas gender was used as a controlling variable. Among boys, scale points of external, among girls, those of internal locus of control showed higher values. External locus of control increased, whereas internal locus of control decreased the risk of substance use, however, the relative role of external/internal locus of control was different according to the type of substance use and the prevalence values. In terms of smoking, lifetime prevalence, whereas in terms of marijuana use, the actual user status was influenced. In addition, while the latter one was also affected by gender, it did not play a role at all in the previous one. All these findings suggest that behavioral control may play a particularly important role in prevention of adolescent substance use. For developing this, methods of cognitive therapy would be effective to be completed with autogenic relaxation training as well.

Psychosocial and cognitive factors associated with adherence to dietary and fluid restriction regimens by people on chronic haemodialysis.

PubMed

Sensky, T; Leger, C; Gilmour, S

1996-01-01

Failure by people on chronic haemodialysis to adhere adequately to dietary and fluid restrictions can have serious medical consequences. Numerous psychosocial factors possibly associated with adherence have been investigated in previous research. However, most previous studies have examined one or a few variables in isolation, and have tended to focus on sociodemographic variables not easily amenable to intervention. Much previous work has tended to ignore potential differences in adherence between male and female dialysands. Sociodemographic and psychosocial factors associated with adherence to dietary and fluid restrictions were investigated in 45 people on haemodialysis attending one renal unit, excluding those with a residual urine volume > 500 ml/day. Multiple regression analyses were used to estimate the contribution to adherence of a range of variables, including gender, age, duration of dialysis, affective disturbance, past psychiatric history, health locus of control, social adjustment and social supports. Adherence to diet (measured by predialysis serum potassium) and to fluid restriction (interdialysis weight gain) were not linked, and had different psychosocial correlates. Regression models of four different aspects of adherence revealed very distinct psychosocial correlates, with contributions to adherence from complex interactions between psychosocial and cognitive variables, notably gender, age, social adjustment, health locus of control, and depression. The findings cast doubt on the results of many previous studies which have used simple models of adherence. Adherence is likely to be influenced in a complex manner by multiple factors including age, gender, locus of control, social adjustment, and past psychiatric history.

Application of Multi-task Sparse Lasso Feature Extraction and Support Vector Machine Regression in the Stellar Atmospheric Parameterization

NASA Astrophysics Data System (ADS)

Gao, Wei; Li, Xiang-ru

2017-07-01

The multi-task learning takes the multiple tasks together to make analysis and calculation, so as to dig out the correlations among them, and therefore to improve the accuracy of the analyzed results. This kind of methods have been widely applied to the machine learning, pattern recognition, computer vision, and other related fields. This paper investigates the application of multi-task learning in estimating the stellar atmospheric parameters, including the surface temperature (Teff), surface gravitational acceleration (lg g), and chemical abundance ([Fe/H]). Firstly, the spectral features of the three stellar atmospheric parameters are extracted by using the multi-task sparse group Lasso algorithm, then the support vector machine is used to estimate the atmospheric physical parameters. The proposed scheme is evaluated on both the Sloan stellar spectra and the theoretical spectra computed from the Kurucz's New Opacity Distribution Function (NEWODF) model. The mean absolute errors (MAEs) on the Sloan spectra are: 0.0064 for lg (Teff /K), 0.1622 for lg (g/(cm · s-2)), and 0.1221 dex for [Fe/H]; the MAEs on the synthetic spectra are 0.0006 for lg (Teff /K), 0.0098 for lg (g/(cm · s-2)), and 0.0082 dex for [Fe/H]. Experimental results show that the proposed scheme has a rather high accuracy for the estimation of stellar atmospheric parameters.

Optical+NIR Quasar Selection with the SDSS and UKIDSS

NASA Astrophysics Data System (ADS)

Mehta, Sajjan S.; Mahon, R. G.; Richards, G. T.; Hewett, P. C.

2010-01-01

We present the details of an optical+near-IR quasar selection technique, which utilizes near-IR data from the UKIDSS Large Area Survey and the optical data from the Sloan Digital Sky Survey in the SDSS's deep "Stripe 82" region, which covers over 200 deg2. Our selection methods primarily consist of isolating potential candidates in giK and gJK color space, in which there exists a significant separation of the stellar locus from the quasar locus. Additionally, we discuss secondary techniques such as comparison of catalog magnitudes with aperture photometry, analysis of SDSS and UKIDSS morphological type classifications, and flag cuts. Our primary color-cut selections include most quasars with redshifts below 3.4, significantly increasing the completeness both to dust reddened quasars and quasars with redshifts z 2.7 in the SDSS footprint. A simple color cut in the UKIDSS LAS Stripe 82 regions reveals 4200 quasar candidates down to K=18. These NIR selections have been used to contribute to the Baryon Oscillation Spectroscopic Survey (BOSS), which is one of the four surveys of the SDSS-III collaboration. We additionally intend to use our NIR techniques to perform an 8-dimensional optical+NIR Bayesian selection of quasars for the AAOmege UKIDSS SDSS (AUS) survey.

Parental Influences, Career Decision-Making Attributions, and Self-Efficacy: Differences for Men and Women?

ERIC Educational Resources Information Center

Lease, Suzanne H.; Dahlbeck, David T.

2009-01-01

This study investigated the relations of maternal and paternal attachment, parenting styles, and career locus of control to college students' career decision self-efficacy and explored whether these relations differed by student gender. Data analysis using hierarchical multiple regression revealed that attachment was relevant for females' career…

Locus of control and academic efficacy in the thoughts of life and death of young Quebec university students.

PubMed

Labelle, Réal; Lachance, Lise

2003-01-01

This study evaluated the role of control and efficacy expectations in the thoughts of life and death of 50 male and 50 female university students and investigated sex differences in this regard. It followed a correlational design and employed measures of tridimensional locus of control, expectations of academic efficacy, thoughts of life and death. A comparison of means revealed that male students did not differ from their female counterparts on any of the variables under study. Stepwise regression coefficients indicated that the two cognitive factors accounted more for thoughts of death than for thoughts of life; expectations of academic efficacy were the single variable that most explained variance. Regression equations by sex showed that thoughts of life were associated with internality and expectations of academic efficacy in females, and that thoughts of death were associated with expectations of academic inefficacy in males. The university counseling personnel should be especially sensitive to youths presenting with expectations of externality and of academic inefficacy. The latter variable seems to be particularly important, regardless of sex.

Multidimensional health locus of control and depressive symptoms in the multi-ethnic population of the Netherlands.

PubMed

van Dijk, Tobias K; Dijkshoorn, Henriëtte; van Dijk, Ad; Cremer, Stephan; Agyemang, Charles

2013-12-01

Ethnic inequalities in health in Western societies are well-documented but poorly understood. We examined associations between health locus of control (HLC) and depressive symptoms among native and non-native Dutch people in the Netherlands. We used hierarchical multiple linear regression analyses on a representative sample of the multi-ethnic population of Amsterdam and The Hague (n = 10,302). HLC was measured with the multidimensional health locus of control scale. Depressive symptoms were measured with the Kessler Psychological Distress scale. Multivariate analyses showed that HLC contributes to ethnic differences in the prevalence of depressive symptoms. Respondents who scored high on external locus of control (PHLC) were more likely to have depressive symptoms than those with a low score on PHLC (β = 0.133, p < 0.001). Conversely, respondents scoring high on internal locus of control (IHLC) were less likely to have depressive symptoms compared to those scoring low on IHLC (β = -0.134, p < 0.001). The associations were most pronounced among Turkish-Dutch and Moroccan-Dutch respondents. Our findings suggest that HLC contributes to ethnic inequalities in depressive symptoms, especially among Turkish and Moroccan ethnic groups. Professionals (e.g. clinicians and policy makers) need to take HLC into account when assessing and treating depression among ethnic minority groups, particularly in Turkish and Moroccan populations. Future research should look further into the associations within these groups.

Coping Styles Mediate the Relationship Between Self-esteem, Health Locus of Control, and Health-Promoting Behavior in Chinese Patients With Coronary Heart Disease.

PubMed

Zou, Huijing; Tian, Qian; Chen, Yuxia; Cheng, Cheng; Fan, Xiuzhen

Health-promoting behavior plays an important role in reducing the burden of coronary heart disease. Self-esteem and health locus of control may contribute to health-promoting behavior, and coping styles may mediate these associations. The aims of our study were to examine whether self-esteem and health locus of control are associated with health-promoting behavior and examine the possible mediating effect of coping styles in patients with coronary heart disease. Health-promoting behavior, self-esteem, health locus of control, and coping styles were assessed in 272 hospitalized patients (60 ± 12 years, 61% male) with coronary heart disease. Hierarchical regression analysis was conducted to analyze the relationships between health-promoting behavior and other variables. Mediation effect was examined according to the methods of Baron and Kenny. The mean score for health-promoting behavior was 2.57 ± 0.51; 38.2% of patients (n = 104) scored lower than 2.5. Self-esteem (β = .139, P < .05), confrontation coping style (β = .491, P < .001), disease duration (≥6 months, β = .147, P < .05), and monthly income (≥1000 RMB [approximately US$154], β = .111, P < .05) were positively associated with health-promoting behavior, accounting for 47.5% of its variance (F = 19.828). Confrontation partly mediated the association between self-esteem and health-promoting behavior and completely mediated the relationship between internal health locus of control and health-promoting behavior. Confrontation plays a mediating role in the association among self-esteem, internal health locus of control, and health-promoting behavior. Strategies should be undertaken to encourage the use of confrontation coping style, which will facilitate health-promoting behavior.

Estimates of the atmospheric parameters of M-type stars: a machine-learning perspective

NASA Astrophysics Data System (ADS)

Sarro, L. M.; Ordieres-Meré, J.; Bello-García, A.; González-Marcos, A.; Solano, E.

2018-05-01

Estimating the atmospheric parameters of M-type stars has been a difficult task due to the lack of simple diagnostics in the stellar spectra. We aim at uncovering good sets of predictive features of stellar atmospheric parameters (Teff, log (g), [M/H]) in spectra of M-type stars. We define two types of potential features (equivalent widths and integrated flux ratios) able to explain the atmospheric physical parameters. We search the space of feature sets using a genetic algorithm that evaluates solutions by their prediction performance in the framework of the BT-Settl library of stellar spectra. Thereafter, we construct eight regression models using different machine-learning techniques and compare their performances with those obtained using the classical χ2 approach and independent component analysis (ICA) coefficients. Finally, we validate the various alternatives using two sets of real spectra from the NASA Infrared Telescope Facility (IRTF) and Dwarf Archives collections. We find that the cross-validation errors are poor measures of the performance of regression models in the context of physical parameter prediction in M-type stars. For R ˜ 2000 spectra with signal-to-noise ratios typical of the IRTF and Dwarf Archives, feature selection with genetic algorithms or alternative techniques produces only marginal advantages with respect to representation spaces that are unconstrained in wavelength (full spectrum or ICA). We make available the atmospheric parameters for the two collections of observed spectra as online material.

Feeling the Pull: A Study of Natural Galactic Accelerometers. II. Kinematics and Mass of the Delicate Stellar Stream of the Palomar 5 Globular Cluster

NASA Astrophysics Data System (ADS)

Ibata, Rodrigo A.; Lewis, Geraint F.; Thomas, Guillaume; Martin, Nicolas F.; Chapman, Scott

2017-06-01

We present two spectroscopic surveys of the tidal stellar stream of the Palomar 5 globular cluster undertaken with the VLT/FLAMES and AAT/AAOmega instruments. We use these data in conjunction with photometric data presented in the previous contribution in this series to classify the survey stars in terms of their probability of belonging to the Palomar 5 stellar stream. We find that high-probability candidates are only found in a very narrow spatial interval surrounding the locus of the stream on the sky. PanSTARRS RR Lyrae stars in this region of the sky are also distributed in a similar manner. The absence of significant “fanning” of this stellar stream confirms that Palomar 5 does not follow a chaotic orbit. Previous studies have found that Palomar 5 is largely devoid of low-mass stars, and we show that this is true also of the stellar populations along the trailing arm out to 6^\\circ . Within this region, which contains 73% of the detected stars, the population is statistically identical to the core, implying that the ejection of the low-mass stars occurred before the formation of the stream. We also present an updated structural model fit to the bound remnant, which yields a total mass of 4297+/- 98{M}ȯ and a tidal radius 0.145+/- 0.009 {kpc}. We estimate the mass of the observed system including the stream to be 12,200 ± 400 M⊙, and the initial mass to have been ~47,000 ± 1500 M⊙. These observational constraints will be employed in our next study to model the dynamics of the system in detail. Based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada–France–Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institute National des Sciences de l’Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii. Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under programme ID 081.B-0258(A) and ID 083.B-0403(A).

Haffner 16 Redux: Revisiting a Young Cluster in the Outer Galaxy

NASA Astrophysics Data System (ADS)

Davidge, T. J.

2017-08-01

Images and spectra recorded with the Gemini Multi-Object Spectrograph on Gemini South are used to investigate the stellar content of the open cluster Haffner 16. The (I\\prime ,g\\prime -I\\prime ) color-magnitude diagram (CMD) constructed from these data extends over 10 mag in I\\prime , sampling the cluster main sequence (MS) and 5 mag of the pre-MS (PMS). The fraction of unresolved equal mass binaries among PMS stars is estimated to be 0.6 ± 0.1. The isochrones do not track the PMS on the CMD, in the sense that the PMS has a shallower slope on the CMD than predicted by the models. Still, a dip in star counts, which is associated with the relaxation of PMS stars onto the MS, is identified near I\\prime =17. The depth and brightness of this feature—as well as the morphology of the cluster MS on the CMD—are matched by models with a slightly sub-solar metallicity that have an age of ˜20 Myr and a distance modulus of 12.3 ± 0.2. A light profile of Haffner 16 is constructed in the W1 filter ({λ }{cen}=3.4 μ {{m}}), which suggests that the cluster is surrounded by a diffuse stellar halo. Spectra of candidate cluster MS and PMS stars selected according to location on the CMD are presented. The spectra show characteristics that are suggestive of a sub-solar metallicity. Hα emission is common among objects on the PMS locus on the CMD near I\\prime =18. It is suggested that the location of the Haffner 16 PMS on the CMD is affected by large-scale cool spot activity, likely induced by rapid stellar rotation.

Empirical Modeling of the Redshift Evolution of the [{\\rm{N}}\\,{\\rm{II}}]/Hα Ratio for Galaxy Redshift Surveys

NASA Astrophysics Data System (ADS)

Faisst, Andreas L.; Masters, Daniel; Wang, Yun; Merson, Alexander; Capak, Peter; Malhotra, Sangeeta; Rhoads, James E.

2018-03-01

We present an empirical parameterization of the [N II]/Hα flux ratio as a function of stellar mass and redshift valid at 0 < z < 2.7 and 8.5< {log}(M/{M}ȯ )< 11.0. This description can (i) easily be applied to simulations for modeling [N II]λ6584 line emission, (ii) deblend [N II] and Hα in current low-resolution grism and narrow-band observations to derive intrinsic Hα fluxes, and (iii) reliably forecast the number counts of Hα emission-line galaxies for future surveys, such as those planned for Euclid and the Wide Field Infrared Survey Telescope (WFIRST). Our model combines the evolution of the locus on the Baldwin, Phillips & Terlevich (BPT) diagram measured in spectroscopic data out to z ∼ 2.5 with the strong dependence of [N II]/Hα on stellar mass and [O III]/Hβ observed in local galaxy samples. We find large variations in the [N II]/Hα flux ratio at a fixed redshift due to its dependency on stellar mass; hence, the assumption of a constant [N II] flux contamination fraction can lead to a significant under- or overestimate of Hα luminosities. Specifically, measurements of the intrinsic Hα luminosity function derived from current low-resolution grism spectroscopy assuming a constant 29% contamination of [N II] can be overestimated by factors of ∼8 at {log}(L)> 43.0 for galaxies at redshifts z ∼ 1.5. This has implications for the prediction of Hα emitters for Euclid and WFIRST. We also study the impact of blended Hα and [N II] on the accuracy of measured spectroscopic redshifts.

On the Evolution of the Central Density of Quiescent Galaxies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tacchella, Sandro; Carollo, C. Marcella; Woo, Joanna

We investigate the origin of the evolution of the population-averaged central stellar mass density (Σ{sub 1}) of quiescent galaxies (QGs) by probing the relation between stellar age and Σ{sub 1} at z ∼ 0. We use the Zurich ENvironmental Study (ZENS), which is a survey of galaxy groups with a large fraction of satellite galaxies. QGs shape a narrow locus in the Σ{sub 1}– M {sub ⋆} plane, which we refer to as Σ{sub 1} ridgeline. Colors of ( B − I ) and ( I − J ) are used to divide QGs into three age categories: young (<2more » Gyr), intermediate (2–4 Gyr), and old (>4 Gyr). At fixed stellar mass, old QGs on the Σ{sub 1} ridgeline have higher Σ{sub 1} than young QGs. This shows that galaxies landing on the Σ{sub 1} ridgeline at later epochs arrive with lower Σ{sub 1}, which drives the zeropoint of the ridgeline down with time. We compare the present-day zeropoint of the oldest population at z = 0 with the zeropoint of the quiescent population 4 Gyr back in time, at z = 0.37. These zeropoints are identical, showing that the intrinsic evolution of individual galaxies after they arrive on the Σ{sub 1} ridgeline must be negligible, or must evolve parallel to the ridgeline during this interval. The observed evolution of the global zeropoint of 0.07 dex over the last 4 Gyr is thus largely due to the continuous addition of newly quenched galaxies with lower Σ{sub 1} at later times (“progenitor bias”). While these results refer to the satellite-rich ZENS sample as a whole, our work suggests a similar age–Σ{sub 1} trend for central galaxies.« less

Kepler AutoRegressive Planet Search (KARPS)

NASA Astrophysics Data System (ADS)

Caceres, Gabriel

2018-01-01

One of the main obstacles in detecting faint planetary transits is the intrinsic stellar variability of the host star. The Kepler AutoRegressive Planet Search (KARPS) project implements statistical methodology associated with autoregressive processes (in particular, ARIMA and ARFIMA) to model stellar lightcurves in order to improve exoplanet transit detection. We also develop a novel Transit Comb Filter (TCF) applied to the AR residuals which provides a periodogram analogous to the standard Box-fitting Least Squares (BLS) periodogram. We train a random forest classifier on known Kepler Objects of Interest (KOIs) using select features from different stages of this analysis, and then use ROC curves to define and calibrate the criteria to recover the KOI planet candidates with high fidelity. These statistical methods are detailed in a contributed poster (Feigelson et al., this meeting).These procedures are applied to the full DR25 dataset of NASA’s Kepler mission. Using the classification criteria, a vast majority of known KOIs are recovered and dozens of new KARPS Candidate Planets (KCPs) discovered, including ultra-short period exoplanets. The KCPs will be briefly presented and discussed.

Examining the locus of age effects on complex span tasks.

PubMed

McCabe, Jennifer; Hartman, Marilyn

2003-09-01

To investigate the locus of age effects on complex span tasks, the authors evaluated the contributions of working memory functions and processing speed. Age differences were found in measures of storage capacity, language processing speed, and lower level speed. Statistically controlling for each of these in hierarchical regressions substantially reduced, but did not eliminate, the complex span age effect. Accounting for lower level speed and storage, however, removed essentially the entire age effect, suggesting that both functions play important and independent roles. Additional evidence for the role of storage capacity was the absence of complex span age differences with span size calibrated to individual word span performance. Explanations for age differences based on inhibition and concurrent task performamce were not supported.

Machine Learning Techniques for Stellar Light Curve Classification

NASA Astrophysics Data System (ADS)

Hinners, Trisha A.; Tat, Kevin; Thorp, Rachel

2018-07-01

We apply machine learning techniques in an attempt to predict and classify stellar properties from noisy and sparse time-series data. We preprocessed over 94 GB of Kepler light curves from the Mikulski Archive for Space Telescopes (MAST) to classify according to 10 distinct physical properties using both representation learning and feature engineering approaches. Studies using machine learning in the field have been primarily done on simulated data, making our study one of the first to use real light-curve data for machine learning approaches. We tuned our data using previous work with simulated data as a template and achieved mixed results between the two approaches. Representation learning using a long short-term memory recurrent neural network produced no successful predictions, but our work with feature engineering was successful for both classification and regression. In particular, we were able to achieve values for stellar density, stellar radius, and effective temperature with low error (∼2%–4%) and good accuracy (∼75%) for classifying the number of transits for a given star. The results show promise for improvement for both approaches upon using larger data sets with a larger minority class. This work has the potential to provide a foundation for future tools and techniques to aid in the analysis of astrophysical data.

Development and validation of a scale measuring the locus of control orientation in relation to socio-dental effects.

PubMed

Acharya, S; Pentapati, K C; Singhal, D K; Thakur, A S

2015-04-01

To develop a socio-dental impact locus of control scale (SILOC) and to study its relationship with oral health status as well as dental attendance. Observational cross-sectional study design. A seven-item SILOC scale based on locus of control and the WHO international classification of diseases' criteria for "Disability" in relation to oral health was developed. In the pilot study, 100 adolescent school children returned completed forms containing the multidimensional health locus of control (MHLC) and the (SILOC) scale. After confirmation of reliability and validity, 509 adolescent school children returned completed SILOC questionnaires and were examined for caries, plaque and gingivitis. A history of postponement of needed dental treatment was also elicited. The SILOC scores were highly correlated with the MHLC scores. Factor analysis revealed a two-factor solution accounting for 59 % of the variance. A Cronbach's alpha of 0.75 showed its internal consistency. Those with higher SILOC scores had greater levels of caries, plaque, gingivitis, and a history of postponing needed dental visits. Multiple logistic regression analysis after adjusting for potential confounders showed that those with high SILOC scores were more likely to have caries (OR = 3.32, p < 0.001), plaque (OR = 1.83, p = 0.026), gingivitis (OR = 1.80, p = 0.012) and a history of 'Postponement of needed dental treatment' (OR = 4.5, p < 0.001) as compared with the others. The SILOC scale showed satisfactory reliability and validity in measuring locus of control orientation in an Indian adolescent population.

Parenting stress in mothers of children with an intellectual disability: the effects of parental cognitions in relation to child characteristics and family support.

PubMed

Hassall, R; Rose, J; McDonald, J

2005-06-01

Recent theories of stress and coping in parents of children with intellectual disabilities (ID) emphasize the importance of cognitive appraisals in influencing parents' levels of stress and their adaptations to difficulties presented by the children. This study investigated the relationships between parental cognitions, child characteristics, family support and parenting stress. The aspects of cognitions studied were: parenting self-esteem (including efficacy and satisfaction) and parental locus of control. The group studied consisted of 46 mothers of children with ID. The Vineland Adaptive Behavior Scales and Maladaptive Behavior Domain were administered by interview. Mothers also completed four questionnaires: the Family Support Scale, the Parenting Sense of Competence Scale, a shortened form of the Parental Locus of Control Scale and the Parenting Stress Index (Short Form). Data were analysed using Pearson's correlation coefficients, partial correlations and a regression analysis. The results indicated that most of the variance in parenting stress was explained by parental locus of control, parenting satisfaction and child behaviour difficulties. Whilst there was also a strong correlation between family support and parenting stress, this was mediated by parental locus of control. The results demonstrate the potential importance of parental cognitions in influencing parental stress levels. It is argued that these results have implications for clinical interventions for promoting parents' coping strategies in managing children with ID and behavioural difficulties.

Characterisation of a candidate dual AGN

NASA Astrophysics Data System (ADS)

Lena, D.; Panizo-Espinar, G.; Jonker, P. G.; Torres, M.; Heida, M.

2018-05-01

We present Chandra and optical observations of a candidate dual AGN discovered serendipitously while searching for recoiling black holes via a cross-correlation between the serendipitous XMM source catalog (2XMMi) and SDSS-DR7 galaxies with a separation no larger than ten times the sum of their Petrosian radii. The system has a stellar mass ratio M1/M2 ≈ 0.7. One of the galaxies (Source 1) shows clear evidence for AGN activity in the form of hard X-ray emission and optical emission-line diagnostics typical of AGN ionisation. The nucleus of the other galaxy (Source 2) has a soft X-ray spectrum, bluer colours, and optical emission line ratios dominated by stellar photoionisation with a "composite" signature, which might indicate the presence of a weak AGN. When plotted on a diagram with X-ray luminosity vs [OIII] luminosity both nuclei fall within the locus defined by local Seyfert galaxies. From the optical spectrum we estimate the electron densities finding n1 < 27 e- cm-3 and n2 ≈ 200 e- cm-3. From a 2D decomposition of the surface brightness distribution we infer that both galaxies host rotationally supported bulges (Sersic index <1). While the active nature of Source 1 can be established with confidence, whether the nucleus of Source 2 is active remains a matter of debate. Evidence that a faint AGN might reside in its nucleus is, however, tantalising.

Multi-Locus Candidate Gene Analyses of Lipid Levels in a Pediatric Turkish Cohort: Lessons Learned on LPL, CETP, LIPC, ABCA1, and SHBG

PubMed Central

Eren, Fatih; Agirbasli, Deniz; White, Marquitta J.; Williams, Scott M

2013-01-01

Abstract Cardiovascular risk factors and atherosclerosis precursors were examined in 365 Turkish children and adolescents. Study participants were recruited at five different state schools. We tested single and multi-locus effects of six polymorphisms from five candidate genes, chosen based on prior known association with lipid levels in adults, for association with low (≤10th percentile) high density lipoprotein cholesterol (HDL-C) and high (≥90th percentile) triglycerides (TG), and the related continuous outcomes. We observed an association between CETP variant rs708272 and low HDL-C (allelic p=0.020, genotypic p=0.046), which was supported by an independent analysis, PRAT (PRAT control p=0.027). Sex-stratified logistic regression analysis showed that the B2 allele of rs708272 decreased odds of being in the lower tenth percentile of HDL-C measurements (OR=0.36, p=0.02) in girls; this direction of effect was also seen in boys but was not significant (OR=0.64, p=0.21). Logistic regression analysis also revealed that the T allele of rs6257 (SHBG) decreased odds of being in the top tenth percentile of TG measurements in boys (OR=0.43, p=0.03). Analysis of lipid levels as a continuous trait revealed a significant association between rs708272 (CETP) and LDL-C levels in males (p=0.02) with the B2B2 genotype group having the lowest mean LDL-C; the same direction of effect was also seen in females (p=0.05). An effect was also seen between rs708272 and HDL-C levels in girls (p=0.01), with the B2B2 genotype having the highest mean HDL-C levels. Multi-locus analysis, using quantitative multifactor dimensionality reduction (qMDR) identified the previously mentioned CETP variant as the best single locus model, and overall model, for predicting HDL-C levels in children. This study provides evidence for association between CETP and low HDL-C phenotype in children, but the results appear to be weaker in children than previous results in adults and may also be subject to gender effects. PMID:23988150

ULTRAVIOLET+INFRARED STAR FORMATION RATES: HICKSON COMPACT GROUPS WITH SWIFT AND SPITZER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tzanavaris, P.; Hornschemeier, A. E.; Immler, S.

2010-06-10

We present Swift UVOT ultraviolet (UV; 1600-3000 A) data with complete three-band UV photometry for a sample of 41 galaxies in 11 nearby (<4500 km s{sup -1}) Hickson Compact Groups (HCGs) of galaxies. We use UVOT uvw2-band (2000 A) photometry to estimate the dust-unobscured component, SFR{sub UV}, of the total star formation rate, SFR{sub TOTAL}. We use Spitzer MIPS 24 {mu}m photometry to estimate SFR{sub IR}, the component of SFR{sub TOTAL} that suffers dust extinction in the UV and is re-emitted in the IR. By combining the two components, we obtain SFR{sub TOTAL} estimates for all HCG galaxies. We obtainmore » total stellar mass, M {sub *}, estimates by means of Two Micron All Sky Survey K{sub s} -band luminosities, and use them to calculate specific star formation rates, SSFR {identical_to} SFR{sub TOTAL}/M {sub *}. SSFR values show a clear and significant bimodality, with a gap between low ({approx}<3.2 x 10{sup -11} yr{sup -1}) and high-SSFR ({approx_gt}1.2 x 10{sup -10} yr{sup -1}) systems. We compare this bimodality to the previously discovered bimodality in {alpha}{sub IRAC}, the MIR activity index from a power-law fit to the Spitzer IRAC 4.5-8 {mu}m data for these galaxies. We find that all galaxies with {alpha}{sub IRAC} {<=} 0 ( >0) are in the high- (low-) SSFR locus, as expected if high levels of star-forming activity power MIR emission from polycyclic aromatic hydrocarbon molecules and a hot dust continuum. Consistent with this finding, all elliptical/S0 galaxies are in the low-SSFR locus, while 22 out of 24 spirals/irregulars are in the high-SSFR locus, with two borderline cases. We further divide our sample into three subsamples (I, II, and III) according to decreasing H I richness of the parent galaxy group to which a galaxy belongs. Consistent with the SSFR and {alpha}{sub IRAC} bimodality, 12 out of 15 type I (11 out of 12 type III) galaxies are in the high- (low-) SSFR locus, while type II galaxies span almost the full range of SSFR values. We use the Spitzer Infrared Nearby Galaxy Survey (SINGS) to construct a comparison subsample of galaxies that (1) match HCG galaxies in J-band total galaxy luminosity and (2) are not strongly interacting and largely isolated. This selection eliminates mostly low-luminosity dwarfs and galaxies with some degree of peculiarity, providing a substantially improved, quiescent control sample. Unlike HCG galaxies, galaxies in the comparison SINGS subsample are continuously distributed both in SSFR and {alpha}{sub IRAC}, although they show ranges in SFR{sub TOTAL} values, morphologies and stellar masses similar to those for HCG systems. We test the SSFR bimodality against a number of uncertainties, and find that these can only lead to its further enhancement. Excluding galaxies belonging to HCGs with three giant galaxies (triplets) leaves both the SSFR and the {alpha}{sub IRAC} bimodality completely unaffected. We interpret these results as further evidence that an environment characterized by high galaxy number densities and low galaxy velocity dispersions, such as the one found in compact groups, plays a key role in accelerating galaxy evolution by enhancing star formation processes in galaxies and favoring a fast transition to quiescence.« less

Ultraviolet+Infrared Star Formation Rates: Hickson Compact Groups with Swift and SPitzer

NASA Technical Reports Server (NTRS)

Tzanavaris, P.; Hornschemeier, A. E.; Gallagher, S. C.; Johnson, K. E.; Gronwall, C.; Immler, S.; Reines, A. E.; Hoversten, E.; Charlton, J. C.

2010-01-01

We present Swift UVOT ultraviolet (UV; 1600-3000 A) data with complete three-band UV photometry for a sample of 41 galaxies in 11 nearby (<4500 km/s) Hickson Compact Groups (HCGs) of galaxies. We use UVOT uvw2-band (2000A) photometry to estimate the dust-unobscured component, SFR(sub uv), of the total star formation rate, SFR(sub TOTAL). We use Spitzer MIPS 24 micron photometry to estimate SFR(sub IR), the component of SFR(sub TOTAL) that suffers dust extinction in the UV and is re-emitted in the IR. By combining the two components, we obtain SFR(sub TOTAL) estimates for all HCG galaxies. We obtain total stellar mass, M(sub *) estimates by means of Two Micron All Sky Survey K(sub s)-band luminosities, and use them to calculate specific star formation rates, SSFR is identical with SFR(sub TOTAL)/ M (sub *). SSFR values show a clear and significant bimodality, with a gap between low (approximately <3.2 x 10(exp -11) / yr) and high-SSFR (approximately > 1.2 x lO)exp -10)/yr) systems. We compare this bimodality to the previously discovered bimodality in alpha-IRAC, the MIR activity index from a power-law fit to the Spitzer IRAC 4.5-8 micron data for these galaxies. We find that all galaxies with alpha-IRAC <= 0 (> 0) are in the high- (low-) SSFR locus, as expected if high levels of star-forming activity power MIR emission from polycyclic aromatic hydrocarbon molecules and a hot dust continuum. Consistent with this finding, all elliptical/SO galaxies are in the low-SSFR locus, while 22 out of 24 spirals / irregulars are in the high-SSFR locus, with two borderline cases. We further divide our sample into three subsamples (I, II, and III) according to decreasing H I richness of the parent galaxy group to which a galaxy belongs. Consistent with the SSFR and alpha-IRAC bimodality, 12 out of 15 type I (11 out of 12 type III) galaxies are in the high- (low-) SSFR locus, while type II galaxies span almost the full range of SSFR values. We use the Spitzer Infrared Nearby Galaxy Survey (SINGS) to construct a comparison subsample of galaxies that (1) match HCG galaxies in J-band total galaxy luminosity and (2) are not strongly interacting and largely isolated. This selection eliminates mostly low-luminosity dwarfs and galaxies with some degree of peculiarity, providing a substantially improved, quiescent control sample. Unlike HCG galaxies, galaxies in the comparison SINGS subsample are continuously distributed both in SSFR and alpha-IRAC, although they show ranges in SFR(sub TOTAL) values, morphologies and stellar masses similar to those for HCG systems. We test the SSFR bimodality against a number of uncertainties, and find that these can only lead to its further enhancement. Excluding galaxies belonging to HCGs with three giant galaxies (triplets) leaves both the SSFR and the alpha-IRAC bimodality completely unaffected. We interpret these results as further evidence that an environment characterized by high galaxy number densities and low galaxy velocity dispersions, such as the one found in compact groups, plays a key role in accelerating galaxy evolution by enhancing star formation processes in galaxies and favoring a fast transition to quiescence.

The Effects of Stroke Type, Locus, and Extent on Long-Term Outcome of Gait Rehabilitation: The LEAPS Experience.

PubMed

Nadeau, Stephen E; Dobkin, Bruce; Wu, Samuel S; Pei, Qinglin; Duncan, Pamela W

2016-08-01

Background Paresis in stroke is largely a result of damage to descending corticospinal and corticobulbar pathways. Recovery of paresis predominantly reflects the impact on the neural consequences of this white matter lesion by reactive neuroplasticity (mechanisms involved in spontaneous recovery) and experience-dependent neuroplasticity, driven by therapy and daily experience. However, both theoretical considerations and empirical data suggest that type of stroke (large vessel distribution/lacunar infarction, hemorrhage), locus and extent of infarction (basal ganglia, right-hemisphere cerebral cortex), and the presence of leukoaraiosis or prior stroke might influence long-term recovery of walking ability. In this secondary analysis based on the 408 participants in the Locomotor Experience Applied Post-Stroke (LEAPS) study database, we seek to address these possibilities. Methods Lesion type, locus, and extent were characterized by the 2 neurologists in the LEAPS trial on the basis of clinical computed tomography and magnetic resonance imaging scans. A series of regression models was used to test our hypotheses regarding the effects of lesion type, locus, extent, and laterality on 2- to 12-month change in gait speed, controlling for baseline gait speed, age, and Berg Balance Scale score. Results Gait speed change at 1 year was significantly reduced in participants with basal ganglia involvement and prior stroke. There was a trend toward reduction of gait speed change in participants with lacunar infarctions. The presence of right-hemisphere cortical involvement had no significant impact on outcome. Conclusions Type, locus, and extent of lesion, and the loss of substrate for neuroplastic effect as a result of prior stroke may affect long-term outcome of rehabilitation of hemiparetic gait. © The Author(s) 2015.

Headache-specific locus of control and migraine-related quality of life: understanding the role of anxiety

PubMed Central

Grinberg, Amy S.; Seng, Elizabeth K.

2017-01-01

Purpose This study examined the relationship between headache-specific locus of control (HSLC) and migraine-related quality of life, and anxiety as a mediator of this relationship. Methods Two hundred and thirty-two people with severe migraine participated in the Treatment of Severe Migraine trial. At baseline, participants completed self-report questionnaires of headache-specific locus of control (HSLC; subscales = Internal, Chance, and Medical Professionals), anxiety, and migraine-related quality of life. Correlations examined relationships between HSLC, anxiety, and migraine-related quality of life; ordinary least squares regression evaluated anxiety as a mediator of the relationship between HSLC and migraine-related quality of life. Results Higher internal HSLC was related to higher overall migraine-related quality of life (ps < .05) and emotion function impairments (p = .012). Anxiety mediated the relationship between internal HSLC and all measures of migraine-specific quality of life (ps < .05). Higher external (medical professionals and chance) HSLC was related to higher migraine-related quality of life impairments (all ps < .001). Conclusions All HSLC beliefs are associated with higher migraine-related quality of life impairments. Anxiety mediates the relationship between internal HSLC and migraine-related quality of life. PMID:27488417

Implication of IL-2/IL-21 region in systemic sclerosis genetic susceptibility

PubMed Central

Diaz-Gallo, Lina-Marcela; Simeon, Carmen P; Broen, Jasper C; Ortego-Centeno, Norberto; Beretta, Lorenzo; Vonk, Madelon C; Carreira, Patricia E; Vargas, Sofia; Román-Ivorra, José Andrés; González-Gay, Miguel A; Tolosa, Carlos; López-Longo, Francisco Javier; Espinosa, Gerard; Vicente, Esther F; Hesselstrand, Roger; Riemekasten, Gabriela; Witte, Torsten; Distler, Jörg H W; Voskuyl, Alexandre E; Schuerwegh, Annemie J; Shiels, Paul G; Nordin, Annika; Padyukov, Leonid; Hoffmann-Vold, Anna-Maria; Scorza, Raffaella; Lunardi, Claudio; Airo, Paolo; van Laar, Jacob M; Hunzelmann, Nicolas; Gathof, Birgit S; Kreuter, Alexander; Herrick, Ariane; Worthington, Jane; Denton, Christopher P; Zhou, Xiaodong; Arnett, Frank C; Fonseca, Carmen; Koeleman, Bobby PC; Assasi, Shervin; Radstake, Timothy R D J; Mayes, Maureen D; Martín, Javier

2013-01-01

Objective The interleukin 2 (IL-2) and interleukin 21 (IL-21) locus at chromosome 4q27 has been associated with several autoimmune diseases, and both genes are related to immune system functions. The aim of this study was to evaluate the role of the IL-2/IL-21 locus in systemic sclerosis (SSc). Patients and methods The case control study included 4493 SSc Caucasian patients and 5856 healthy controls from eight Caucasian populations (Spain, Germany, The Netherlands, USA, Italy, Sweden, UK and Norway). Four single nucleotide polymorphisms (rs2069762, rs6822844, rs6835457 and rs907715) were genotyped using TaqMan allelic discrimination assays. Results We observed evidence of association of the rs6822844 and rs907715 variants with global SSc (pc=6.6E-4 and pc=7.2E-3, respectively). Similar statistically significant associations were observed for the limited cutaneous form of the disease. The conditional regression analysis suggested that the most likely genetic variation responsible for the association was the rs6822844 polymorphism. Consistently, the rs2069762A-rs6822844T-rs6835457G-rs907715T allelic combination showed evidence of association with SSc and limited cutaneous SSc subtype (pc=1.7E-03 and pc=8E-4, respectively). Conclusions These results suggested that the IL-2/IL-21 locus influences the genetic susceptibility to SSc. Moreover, this study provided further support for the IL-2/IL-21 locus as a common genetic factor in autoimmune diseases. PMID:23172754

A Color-locus Method for Mapping R V Using Ensembles of Stars

NASA Astrophysics Data System (ADS)

Lee, Albert; Green, Gregory M.; Schlafly, Edward F.; Finkbeiner, Douglas P.; Burgett, William; Chambers, Ken; Flewelling, Heather; Hodapp, Klaus; Kaiser, Nick; Kudritzki, Rolf-Peter; Magnier, Eugene; Metcalfe, Nigel; Wainscoat, Richard; Waters, Christopher

2018-02-01

We present a simple but effective technique for measuring angular variation in R V across the sky. We divide stars from the Pan-STARRS1 catalog into Healpix pixels and determine the posterior distribution of reddening and R V for each pixel using two independent Monte Carlo methods. We find the two methods to be self-consistent in the limits where they are expected to perform similarly. We also find some agreement with high-precision photometric studies of R V in Perseus and Ophiuchus, as well as with a map of reddening near the Galactic plane based on stellar spectra from APOGEE. While current studies of R V are mostly limited to isolated clouds, we have developed a systematic method for comparing R V values for the majority of observable dust. This is a proof of concept for a more rigorous Galactic reddening map.

Serendipitous Discovery of RR Lyrae Stars in the Leo V Ultra-faint Galaxy

NASA Astrophysics Data System (ADS)

Medina, Gustavo E.; Muñoz, Ricardo R.; Vivas, A. Katherina; Förster, Francisco; Carlin, Jeffrey L.; Martinez, Jorge; Galbany, Lluis; González-Gaitán, Santiago; Hamuy, Mario; de Jaeger, Thomas; Maureira, Juan Carlos; San Martín, Jaime

2017-08-01

During the analysis of RR Lyrae stars (RRLs) discovered in the High Cadence Transient Survey (HiTS) taken with the Dark Energy Camera at the 4 m telescope at Cerro Tololo Inter-American Observatory, we found a group of three very distant, fundamental mode pulsator RR Lyrae (type ab). The location of these stars agrees with them belonging to the Leo V ultra-faint satellite galaxy, for which no variable stars have been reported to date. The heliocentric distance derived for Leo V based on these stars is 173 ± 5 kpc. The pulsational properties (amplitudes and periods) of these stars locate them within the locus of the Oosterhoff II group, similar to most other ultra-faint galaxies with known RRLs. This serendipitous discovery shows that distant RRLs may be used to search for unknown faint stellar systems in the outskirts of the Milky Way.

Analysis of the SFR-M∗ plane at z < 3: single fitting versus multi-Gaussian decomposition

NASA Astrophysics Data System (ADS)

Bisigello, L.; Caputi, K. I.; Grogin, N.; Koekemoer, A.

2018-01-01

The analysis of galaxies on the star formation rate-stellar mass (SFR-M∗) plane is a powerful diagnostic for galaxy evolution at different cosmic times. We consider a sample of 24 463 galaxies from the CANDELS/GOODS-S survey to conduct a detailed analysis of the SFR-M∗ relation at redshifts re than three dex in stellar mass. To obtain SFR estimates, we utilise mid- and far-IR photometry when available, and rest-UV fluxes for all the other galaxies. We perform our analysis in different redshift bins, with two different methods: 1) a linear regression fitting of all star-forming galaxies, defined as those with specific SFRs log 10(sSFR/ yr-1) > -9.8, similarly to what is typically done in the literature; 2) a multi-Gaussian decomposition to identify the galaxy main sequence (MS), the starburst sequence and the quenched galaxy cloud. We find that the MS slope becomes flatter when higher stellar mass cuts are adopted, and that the apparent slope change observed at high masses depends on the SFR estimation method. In addition, the multi-Gaussian decomposition reveals the presence of a starburst population which increases towards low stellar masses and high redshifts. We find that starbursts make up 5% of all galaxies at z = 0.5-1.0, while they account for 16% of galaxies at 2

On the universal stellar law

NASA Astrophysics Data System (ADS)

Krot, Alexander

In this work, we consider a statistical theory of gravitating spheroidal bodies to derive and develop the universal stellar law for extrasolar systems. Previously, the statistical theory for a cosmogonic body forming (so-called spheroidal body)has been proposed [1-3]. This theory starts from the conception for forming a spheroidal body inside a gas-dust protoplanetary nebula; it permits us to derive the form of distribution functions, mass density, gravitational potentials and strengths both for immovable and rotating spheroidal bodies as well as to find the distribution function of specific angular momentum[1-3]. If we start from the conception for forming a spheroidal body as a protostar (in particular, proto-Sun) inside a prestellar (presolar) nebula then the derived distribution functions of particle (as well as the mass density of an immovable spheroidal body) characterizes the first stage of evolution: from a prestellar molecular cloud (the presolar nebula) to the forming core of protostar (the proto-Sun) together with its shell as a stellar nebula (the solar nebula). This work derives the equation of state of an ideal stellar substance based on conception of gravitating spheroidal body. Using this equation, we obtain the universal stellar law (USL) for the planetary systems connecting temperature, size and mass of each of stars. This work also considers the Solar corona in the connection with USL. Then it is accounting under calculation of the ratio of temperature of the Solar corona to effective temperature of the Sun’ surfaceand modification of USL. To test justice of the modified USLfor different types of stars, the temperature of stellar corona is estimated. The prediction of parameters of stars is carrying out by means of the modified USL,as well as the Hertzsprung-Russell’s dependence [5-7]is derivedby means of USL directly. This paper also shows that knowledge of some characteristics for multi-planet extrasolar systems refines own parameters of stars. In this connection, comparison with estimations of temperatures using of the regression dependences for multi-planet extrasolar systems [8] testifies the obtained results entirely. References 1. Krot, A.M.:2009, A statistical approach to investigate the formation of the solar system. Chaos, Solitons and Fractals41(3), 1481-1500. 2. Krot, A.M.:2012, A models of forming planets and distribution of planetary distances and orbits in the solar system based on the statistical theory of spheroidal bodies. In:Solar System: Structure, Formation and Exploration, ch.9 (Ed. by Matteo de Rossi). New York, Nova Science Publishers, pp. 201-264. - ISBN: 978-1-62100-057-0. 3. Krot, A. M.:2012, A statistical theory of formation of gravitating cosmogonicbodies. Minsk,Bel. Navuka, 4. 448 p. - ISBN 978-985-08-1442-5 [monograph in Russian]. 5. Eddington, A.S.: 1916,On the radiative equilibrium of the stars.Mon. Not. Roy. Astron. Soc.84 (7), 525-528. 6. Jeans, J.: 1929, Astronomy and cosmogony. Cambridge, University Press. 7. Chandrasekhar, S.:1939, An introduction to the study of stellar structure.Cambridge, University Press. 8. Pintr, P., Peřinová, V., Lukš, A., Pathak, A.:2013, Statistical and regression analyses of detected extrasolar systems. Planetary and Space Science, 75(1), 37-45.

ZFIRE: using Hα equivalent widths to investigate the in situ initial mass function at z ˜ 2

NASA Astrophysics Data System (ADS)

Nanayakkara, Themiya; Glazebrook, Karl; Kacprzak, Glenn G.; Yuan, Tiantian; Fisher, David; Tran, Kim-Vy; Kewley, Lisa J.; Spitler, Lee; Alcorn, Leo; Cowley, Michael; Labbe, Ivo; Straatman, Caroline; Tomczak, Adam

2017-07-01

We use the ZFIRE (http://zfire.swinburne.edu.au) survey to investigate the high-mass slope of the initial mass function (IMF) for a mass-complete (log_{10({M}_*/M_{⊙})˜ 9.3}) sample of 102 star-forming galaxies at z ˜ 2 using their Hα equivalent widths (Hα EWs) and rest-frame optical colours. We compare dust-corrected Hα EW distributions with predictions of star formation histories (SFHs) from pegase.2 and starburst synthetic stellar population models. We find an excess of high Hα EW galaxies that are up to 0.3-0.5 dex above the model-predicted Salpeter IMF locus and the Hα EW distribution is much broader (10-500 Å) than can easily be explained by a simple monotonic SFH with a standard Salpeter-slope IMF. Though this discrepancy is somewhat alleviated when it is assumed that there is no relative attenuation difference between stars and nebular lines, the result is robust against observational biases, and no single IMF (I.e. non-Salpeter slope) can reproduce the data. We show using both spectral stacking and Monte Carlo simulations that starbursts cannot explain the EW distribution. We investigate other physical mechanisms including models with variations in stellar rotation, binary star evolution, metallicity and the IMF upper-mass cut-off. IMF variations and/or highly rotating extreme metal-poor stars (Z ˜ 0.1 Z⊙) with binary interactions are the most plausible explanations for our data. If the IMF varies, then the highest Hα EWs would require very shallow slopes (Γ > -1.0) with no one slope able to reproduce the data. Thus, the IMF would have to vary stochastically. We conclude that the stellar populations at z ≳ 2 show distinct differences from local populations and there is no simple physical model to explain the large variation in Hα EWs at z ˜ 2.

A longitudinal study of posttraumatic stress symptoms and their predictors in rescue workers after a firework factory disaster.

PubMed

Ask, Elklit; Gudmundsdottir, Drifa

2014-01-01

This is a follow up study on rescue workers participating in the primary rescue during and immediately after the explosion of a firework factory. We aimed to estimate the possible PTSD prevalence at five and 18 months post disaster, determining if the level of PTSD symptoms at 18 months could be predicted from factors measured at five months. We included measures of posttraumatic symptoms, social support, locus of control and demographic questions. The possible PTSD prevalence rose from 1.6% (n = 465) at five months post disaster to 3.1% (n = 130) at 18 months. A hierarchical linear regression predicted 59% of PTSD symptoms variance at 18 months post disaster. In the final regression, somatization explained the greatest part of the symptom variance (42%), followed by locus of control (29%) and major life events prior to and right after the disaster (23%). Rescue workers seemed to be relatively robust to traumatic exposure: The prevalence of possible PTSD in our study was even lower than previous studies, probably because of the less severe consequences of the disaster studied. Furthermore, we found that PTSD symptom level at 18 months post disaster was highly predicted by psychological factors, particularly by somatization. However, further investigations of traumatic responding are required in this population.

Life satisfaction and its correlates in older women with osteoarthritis.

PubMed

Tak, Sunghee H; Laffrey, Shirley C

2003-01-01

To identify the relationships among functional disability, chronic daily stress, coping strategies, beliefs about personal control, social support, and life satisfaction in older women with osteoarthritis. A descriptive, correlational design was used. The study participants were 107 women aged 60 years or older. Study participants completed six survey questionnaires and a demographic form. Bivariate correlational analyses showed that older women with poorer functional ability experienced greater chronic daily stress, reported more frequent use of emotion-focused coping strategies, and had a higher chance health locus of control. A hierarchic regression analysis revealed that the perceived social support and internal health locus of control significantly contributed to the prediction of life satisfaction after demographic, illness-related, and stress-related variables were controlled. Stress management strategies matched to the participants' style of coping process can increase their sense of control over their health and enhance their social networks and activities.

Academic procrastination: the relationship between causal attribution styles and behavioral postponement.

PubMed

Badri Gargari, Rahim; Sabouri, Hossein; Norzad, Fatemeh

2011-01-01

This research was conducted to study the relationship between attribution and academic procrastination in University Students. The subjects were 203 undergraduate students, 55 males and 148 females, selected from English and French language and literature students of Tabriz University. Data were gathered through Procrastination Assessment Scale-student (PASS) and Causal Dimension Scale (CDA) and were analyzed by multiple regression analysis (stepwise). The results showed that there was a meaningful and negative relation between the locus of control and controllability in success context and academic procrastination. Besides, a meaningful and positive relation was observed between the locus of control and stability in failure context and procrastination. It was also found that 17% of the variance of procrastination was accounted by linear combination of attributions. We believe that causal attribution is a key in understanding procrastination in academic settings and is used by those who have the knowledge of Causal Attribution styles to organize their learning.

[Gender role orientation and tobacco and alcohol use among youth in Morelos, Mexico].

PubMed

Chávez-Ayala, Rubén; Rivera-Rivera, Leonor; Leyva-López, Ahideé; Sánchez-Estrada, Marcela; Lazcano-Ponce, Eduardo

2013-01-01

To quantify the association between gender role orientation and tobacco and alcohol use among young people of the State of Morelos. Study conducted in 2004-2005, students aged 14 to 24 years (n = 1 730). Sociodemographic variables (area of residence, socioeconomic status), family (parental education and violence), psycho-sociological (gender role, self-esteem, depression, alcohol consumption, tobacco, locus of control, sexual abuse). Logistic regression analysis. Factors associated with use of tobacco: In women, being androgynous undesirable, masculine role, attempted sexual abuse and urban areas. For men, depression and submission. Factors associated with alcohol use: In women, masculine gender role; and in men to be older than 20 years, living in semi-urban and urban area, and internal locus. The machismo is one of the gender role orientations with greater association with the use of tobacco primarily in girls in Mexico, and the masculine or instrumental role with alcohol.

Characterization of a candidate dual AGN

NASA Astrophysics Data System (ADS)

Lena, D.; Panizo-Espinar, G.; Jonker, P. G.; Torres, M. A. P.; Heida, M.

2018-07-01

We present Chandra and optical observations of a candidate dual active galactic nucleus (AGN) discovered serendipitously while searching for recoiling black holes via a cross-correlation between the serendipitous XMM source catalogue (2XMMi) and SDSS-DR7 galaxies with a separation no larger than 10 times the sum of their Petrosian radii. The system has a stellar mass ratio M1/M2 ≈ 0.7. One of the galaxies (Source 1) shows clear evidence for AGN activity in the form of hard X-ray emission and optical emission-line diagnostics typical of AGN ionization. The nucleus of the other galaxy (Source 2) has a soft X-ray spectrum, bluer colours, and optical emission-line ratios dominated by stellar photoionization with a `composite' signature, which might indicate the presence of a weak AGN. When plotted on a diagram with X-ray luminosity versus [OIII] luminosity, both nuclei fall within the locus defined by local Seyfert galaxies. From the optical spectrum, we estimate the electron densities finding n1 < 27 e- cm-3 and n2 ≈ 200 e- cm-3. From a 2D decomposition of the surface brightness distribution, we infer that both galaxies host rotationally supported bulges (Sérsic index <1). While the active nature of Source 1 can be established with confidence, whether the nucleus of Source 2 is active remains a matter of debate. Evidence that a faint AGN might reside in its nucleus is, however, tantalizing.

ELM: an Algorithm to Estimate the Alpha Abundance from Low-resolution Spectra

NASA Astrophysics Data System (ADS)

Bu, Yude; Zhao, Gang; Pan, Jingchang; Bharat Kumar, Yerra

2016-01-01

We have investigated a novel methodology using the extreme learning machine (ELM) algorithm to determine the α abundance of stars. Applying two methods based on the ELM algorithm—ELM+spectra and ELM+Lick indices—to the stellar spectra from the ELODIE database, we measured the α abundance with a precision better than 0.065 dex. By applying these two methods to the spectra with different signal-to-noise ratios (S/Ns) and different resolutions, we found that ELM+spectra is more robust against degraded resolution and ELM+Lick indices is more robust against variation in S/N. To further validate the performance of ELM, we applied ELM+spectra and ELM+Lick indices to SDSS spectra and estimated α abundances with a precision around 0.10 dex, which is comparable to the results given by the SEGUE Stellar Parameter Pipeline. We further applied ELM to the spectra of stars in Galactic globular clusters (M15, M13, M71) and open clusters (NGC 2420, M67, NGC 6791), and results show good agreement with previous studies (within 1σ). A comparison of the ELM with other widely used methods including support vector machine, Gaussian process regression, artificial neural networks, and linear least-squares regression shows that ELM is efficient with computational resources and more accurate than other methods.

Locus Coeruleus Neuron Density and Parkinsonism in Older Adults without Parkinson’s Disease

PubMed Central

Buchman, Aron S.; Nag, Sukriti; Shulman, Joshua M.; Lim, Andrew S.P.; VanderHorst, Veronique G.J.M.; Leurgans, Sue E.; Schneider, Julie A.; Bennett, David A.

2013-01-01

Objective Prior work has showed that nigral neuron density is related to the severity of parkinsonism proximate to death in older persons without a clinical diagnosis of Parkinson’s disease (PD). We tested the hypothesis that neuron density in other brainstem aminergic nuclei is also related to the severity of parkinsonism. Design We studied brain autopsies from 125 deceased older adults without PD enrolled in the Memory and Aging Project, a clinical-pathologic investigation. Parkinsonism was assessed with a modified version of the Unified Parkinson’s Disease Rating Scale (UPDRS). We measured neuron density in the substantia nigra, ventral tegmental area, locus coeruleus and dorsal raphe; and postmortem indices of Lewy body Alzheimer’s disease and cerebrovascular pathologies. Results Mean age at death was 88.0 and global parkinsonism was 14.8 (SD=9.50). In a series of regression models which controlled for demographics and neuron density in the substantia nigra, neuron density in the locus coeruleus (Estimate, −0.261, S.E., 0.117, p=0.028) but not in the ventral tegmental area or dorsal raphe was associated with the severity of global parkinsonism proximate to death. These findings were unchanged in models which controlled for post-mortem interval, whole brain weight and other common neuropathologies including Alzheimer’s disease and Lewy body pathology and cerebrovascular vascular pathologies. Conclusion In older adults without a clinical diagnosis of PD, neuron density in locus coeruleus nuclei is associated with the severity of parkinsonism and may contribute to late-life motor impairments. PMID:23038629

Chitinase-3-like 1 protein (CHI3L1) locus influences cerebrospinal fluid levels of YKL-40.

PubMed

Deming, Yuetiva; Black, Kathleen; Carrell, David; Cai, Yefei; Del-Aguila, Jorge L; Fernandez, Maria Victoria; Budde, John; Ma, ShengMei; Saef, Benjamin; Howells, Bill; Bertelsen, Sarah; Huang, Kuan-Lin; Sutphen, Courtney L; Tarawneh, Rawan; Fagan, Anne M; Holtzman, David M; Morris, John C; Goate, Alison M; Dougherty, Joseph D; Cruchaga, Carlos

2016-11-10

Alzheimer's disease (AD) pathology appears several years before clinical symptoms, so identifying ways to detect individuals in the preclinical stage is imperative. The cerebrospinal fluid (CSF) Tau/Aβ 42 ratio is currently the best known predictor of AD status and cognitive decline, and the ratio of CSF levels of chitinase-3-like 1 protein (CHI3L1, YKL-40) and amyloid beta (Aβ 42 ) were reported as predictive, but individual variability and group overlap inhibits their utility for individual diagnosis making it necessary to find ways to improve sensitivity of these biomarkers. We used linear regression to identify genetic loci associated with CSF YKL-40 levels in 379 individuals (80 cognitively impaired and 299 cognitively normal) from the Charles F and Joanne Knight Alzheimer's Disease Research Center. We tested correlations between YKL-40 and CSF Tau/Aβ 42 ratio, Aβ 42 , tau, and phosphorylated tau (ptau 181 ). We used studentized residuals from a linear regression model of the log-transformed, standardized protein levels and the additive reference allele counts from the most significant locus to adjust YKL-40 values and tested the differences in correlations with CSF Tau/Aβ 42 ratio, Aβ 42 , tau, and ptau 181 . We found that genetic variants on the CH13L1 locus were significantly associated with CSF YKL-40 levels, but not AD risk, age at onset, or disease progression. The most significant variant is a reported expression quantitative trait locus for CHI3L1, the gene which encodes YKL-40, and explained 12.74 % of the variance in CSF YKL-40 in our study. YKL-40 was positively correlated with ptau 181 (r = 0.521) and the strength of the correlation significantly increased with the addition of genetic information (r = 0.573, p = 0.006). CSF YKL-40 levels are likely a biomarker for AD, but we found no evidence that they are an AD endophenotype. YKL-40 levels are highly regulated by genetic variation, and by including genetic information the strength of the correlation between YKL-40 and ptau 181 levels is significantly improved. Our results suggest that studies of potential biomarkers may benefit from including genetic information.

Regression and Data Mining Methods for Analyses of Multiple Rare Variants in the Genetic Analysis Workshop 17 Mini-Exome Data

PubMed Central

Bailey-Wilson, Joan E.; Brennan, Jennifer S.; Bull, Shelley B; Culverhouse, Robert; Kim, Yoonhee; Jiang, Yuan; Jung, Jeesun; Li, Qing; Lamina, Claudia; Liu, Ying; Mägi, Reedik; Niu, Yue S.; Simpson, Claire L.; Wang, Libo; Yilmaz, Yildiz E.; Zhang, Heping; Zhang, Zhaogong

2012-01-01

Group 14 of Genetic Analysis Workshop 17 examined several issues related to analysis of complex traits using DNA sequence data. These issues included novel methods for analyzing rare genetic variants in an aggregated manner (often termed collapsing rare variants), evaluation of various study designs to increase power to detect effects of rare variants, and the use of machine learning approaches to model highly complex heterogeneous traits. Various published and novel methods for analyzing traits with extreme locus and allelic heterogeneity were applied to the simulated quantitative and disease phenotypes. Overall, we conclude that power is (as expected) dependent on locus-specific heritability or contribution to disease risk, large samples will be required to detect rare causal variants with small effect sizes, extreme phenotype sampling designs may increase power for smaller laboratory costs, methods that allow joint analysis of multiple variants per gene or pathway are more powerful in general than analyses of individual rare variants, population-specific analyses can be optimal when different subpopulations harbor private causal mutations, and machine learning methods may be useful for selecting subsets of predictors for follow-up in the presence of extreme locus heterogeneity and large numbers of potential predictors. PMID:22128066

Examination of X chromosome markers in Rett syndrome: Exclusion mapping with a novel variation on multilocus linkage analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ellison, K.A.; Fill, C.P.; Terwililger, J.

Rett syndrome is a neurologic disorder characterized by early normal development followed by regression, acquired deceleration of head growth, autism, ataxia, and sterotypic hand movements. The exclusive occurrence of the syndrome in females and the occurrence of a few familial cases with inheritance through maternal lines suggest that this disorder is most likely secondary to a mutation on the X chromosome. To address this hypothesis and to identify candidate regions for the Rett syndrome gene locus, genotypic analysis was performed in two families with maternally related affected half-sisters by using 63 DNA markers from the X chromosome. Nineteen of themore » loci studied were chosen for multipoint linkage analysis because they have been previously genetically mapped using a large number of meioses from reference families. Using the exclusion criterion of a lod score less than [minus]2, the authors were able to exclude the region between the Duchenne muscular dystrophy locus and the DXS456 locus. This region extends from Xp21.2 to Xq21-q23. The use of the multipoint linkage analysis approach outlined in this study should allow the exclusion of additional regions of the X chromosome as new markers are analyzed.« less

Primordial helium abundance determination using sulphur as metallicity tracer

NASA Astrophysics Data System (ADS)

Fernández, Vital; Terlevich, Elena; Díaz, Angeles I.; Terlevich, Roberto; Rosales-Ortega, F. F.

2018-05-01

The primordial helium abundance YP is calculated using sulphur as metallicity tracer in the classical methodology (with YP as an extrapolation of Y to zero metals). The calculated value, YP, S = 0.244 ± 0.006, is in good agreement with the estimate from the Planck experiment, as well as, determinations in the literature using oxygen as the metallicity tracer. The chemical analysis includes the sustraction of the nebular continuum and of the stellar continuum computed from simple stellar population synthesis grids. The S+2 content is measured from the near infrared [SIII]λλ9069Å, 9532Å lines, while an ICF(S3 +) is proposed based on the Ar3 +/Ar2 + fraction. Finally, we apply a multivariable linear regression using simultaneously oxygen, nitrogen and sulphur abundances for the same sample to determine the primordial helium abundance resulting in YP - O, N, S = 0.245 ± 0.007.

Heritability of submaximal exercise heart rate response to exercise training is accounted for by nine SNPs.

PubMed

Rankinen, Tuomo; Sung, Yun Ju; Sarzynski, Mark A; Rice, Treva K; Rao, D C; Bouchard, Claude

2012-03-01

Endurance training-induced changes in hemodynamic traits are heritable. However, few genes associated with heart rate training responses have been identified. The purpose of our study was to perform a genome-wide association study to uncover DNA sequence variants associated with submaximal exercise heart rate training responses in the HERITAGE Family Study. Heart rate was measured during steady-state exercise at 50 W (HR50) on 2 separate days before and after a 20-wk endurance training program in 483 white subjects from 99 families. Illumina HumanCNV370-Quad v3.0 BeadChips were genotyped using the Illumina BeadStation 500GX platform. After quality control procedures, 320,000 single-nucleotide polymorphisms (SNPs) were available for the genome-wide association study analyses, which were performed using the MERLIN software package (single-SNP analyses and conditional heritability tests) and standard regression models (multivariate analyses). The strongest associations for HR50 training response adjusted for age, sex, body mass index, and baseline HR50 were detected with SNPs at the YWHAQ locus on chromosome 2p25 (P = 8.1 × 10(-7)), the RBPMS locus on chromosome 8p12 (P = 3.8 × 10(-6)), and the CREB1 locus on chromosome 2q34 (P = 1.6 × 10(-5)). In addition, 37 other SNPs showed P values <9.9 × 10(-5). After removal of redundant SNPs, the 10 most significant SNPs explained 35.9% of the ΔHR50 variance in a multivariate regression model. Conditional heritability tests showed that nine of these SNPs (all intragenic) accounted for 100% of the ΔHR50 heritability. Our results indicate that SNPs in nine genes related to cardiomyocyte and neuronal functions, as well as cardiac memory formation, fully account for the heritability of the submaximal heart rate training response.

The effect of intimate exposure to alcohol abuse on the acquisition of knowledge about drinking.

PubMed

Rainer, J P

1994-01-01

This study explored how an alcohol education program might be structured to effectively educate college students about the consequences of alcohol use. The primary hypothesis tested stated that individuals would vary significantly in the amount of knowledge learned from a structured alcohol education workshop, based on the degree of familial or social exposure s/he has had to alcohol abuse. Social learning variables of locus of control, dogmatism, and expectancy for risk were tested for interaction with degree of exposure, to determine their influence on learning. A pretest-posttest control group was employed with a sample of 66 undergraduate college students. A four hour alcohol education program was administered to teach cognitive information and fact about alcohol, with a goal of facilitating responsible use/nonuse of alcohol. The Student Drinking Questionnaire measured acquisition of knowledge. The Adult Nowicki-Strickland Internal/External Scale measured locus of control, and Schultze's Short Dogmatism Scale measured dogmatism. The researcher developed an instrument for expectancy for risk. Multiple regression analyses yielded prediction equations for the variables under study. For the sample group, results demonstrated that a significant portion of the variance in the residualized posttest scores was accounted for by level of exposure and dogmatism. When the sample was blocked according to intimate or social exposure, dogmatism was the only construct entering the regression equation at a significant level for the intimate exposure group. None of the constructs were able to predict any of the residualized posttest scores for the social exposure group. It was concluded that: (1) Students in the sample learned differentially based on the degree of intimate exposure of alcohol; (2) Dogmatism is a moderating variable with acquisition of knowledge for those intimately exposed to alcohol abuse, but locus of control and expectancy for risk are not; and (3) Further research is needed to study the effects of differential learning goals set for different populations.

Heritability of submaximal exercise heart rate response to exercise training is accounted for by nine SNPs

PubMed Central

Sung, Yun Ju; Sarzynski, Mark A.; Rice, Treva K.; Rao, D. C.; Bouchard, Claude

2012-01-01

Endurance training-induced changes in hemodynamic traits are heritable. However, few genes associated with heart rate training responses have been identified. The purpose of our study was to perform a genome-wide association study to uncover DNA sequence variants associated with submaximal exercise heart rate training responses in the HERITAGE Family Study. Heart rate was measured during steady-state exercise at 50 W (HR50) on 2 separate days before and after a 20-wk endurance training program in 483 white subjects from 99 families. Illumina HumanCNV370-Quad v3.0 BeadChips were genotyped using the Illumina BeadStation 500GX platform. After quality control procedures, 320,000 single-nucleotide polymorphisms (SNPs) were available for the genome-wide association study analyses, which were performed using the MERLIN software package (single-SNP analyses and conditional heritability tests) and standard regression models (multivariate analyses). The strongest associations for HR50 training response adjusted for age, sex, body mass index, and baseline HR50 were detected with SNPs at the YWHAQ locus on chromosome 2p25 (P = 8.1 × 10−7), the RBPMS locus on chromosome 8p12 (P = 3.8 × 10−6), and the CREB1 locus on chromosome 2q34 (P = 1.6 × 10−5). In addition, 37 other SNPs showed P values <9.9 × 10−5. After removal of redundant SNPs, the 10 most significant SNPs explained 35.9% of the ΔHR50 variance in a multivariate regression model. Conditional heritability tests showed that nine of these SNPs (all intragenic) accounted for 100% of the ΔHR50 heritability. Our results indicate that SNPs in nine genes related to cardiomyocyte and neuronal functions, as well as cardiac memory formation, fully account for the heritability of the submaximal heart rate training response. PMID:22174390

Causal relationship between the AHSG gene and BMD through fetuin-A and BMI: multiple mediation analysis.

PubMed

Sritara, C; Thakkinstian, A; Ongphiphadhanakul, B; Chailurkit, L; Chanprasertyothin, S; Ratanachaiwong, W; Vathesatogkit, P; Sritara, P

2014-05-01

Using mediation analysis, a causal relationship between the AHSG gene and bone mineral density (BMD) through fetuin-A and body mass index (BMI) mediators was suggested. Fetuin-A, a multifunctional protein of hepatic origin, is associated with bone mineral density. It is unclear if this association is causal. This study aimed at clarification of this issue. A cross-sectional study was conducted among 1,741 healthy workers from the Electricity Generating Authority of Thailand (EGAT) cohort. The alpha-2-Heremans-Schmid glycoprotein (AHSG) rs2248690 gene was genotyped. Three mediation models were constructed using seemingly unrelated regression analysis. First, the ln[fetuin-A] group was regressed on the AHSG gene. Second, the BMI group was regressed on the AHSG gene and the ln[fetuin-A] group. Finally, the BMD model was constructed by fitting BMD on two mediators (ln[fetuin-A] and BMI) and the independent AHSG variable. All three analyses were adjusted for confounders. The prevalence of the minor T allele for the AHSG locus was 15.2%. The AHSG locus was highly related to serum fetuin-A levels (P < 0.001). Multiple mediation analyses showed that AHSG was significantly associated with BMD through the ln[fetuin-A] and BMI pathway, with beta coefficients of 0.0060 (95% CI 0.0038, 0.0083) and 0.0030 (95% CI 0.0020, 0.0045) at the total hip and lumbar spine, respectively. About 27.3 and 26.0% of total genetic effects on hip and spine BMD, respectively, were explained by the mediation effects of fetuin-A and BMI. Our study suggested evidence of a causal relationship between the AHSG gene and BMD through fetuin-A and BMI mediators.

Marital status, social capital and health locus of control: a population-based study.

PubMed

Lindström, M; Rosvall, M

2012-09-01

To investigate the association between marital status and lack of internal health locus of control (HLC), taking economic stress and trust into account. Cross-sectional study. The public health survey Skåne 2008 is a postal questionnaire study (55% participation rate). A random sample was invited to participate, and 28,198 individuals aged 18-80 years agreed. Logistic regression models were used to discern associations between marital status and lack of internal HLC. The multiple regression analyses included age, country of birth, education, economic stress and 'horizontal' trust. In total, 33.7% of the men and 31.8% of the women lacked internal HLC. After age-adjustments, the unmarried and divorced men and the widowed women displayed significantly higher odds ratios of lack of internal HLC. The significantly higher odds ratios only remained for unmarried men throughout the multiple analyses. In contrast, divorced women had significantly lower odds ratios of lack of internal HLC than married women after adjustments for economic stress. Health promotion regarding HLC and related behaviours should consider men and women who are not cohabiting. Health promotion should particularly consider unmarried men due to their higher propensity to lack internal HLC. The economic conditions and exposure to economic stress among widowed and divorced women should also be highlighted. Copyright © 2012 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Work Stress, Burnout, and Social and Personal Resources among Direct Care Workers

PubMed Central

Gray-Stanley, Jennifer A.; Muramatsu, Naoko

2014-01-01

Work stress is endemic among direct care workers (DCWs) who serve people with intellectual and developmental disabilities. Social resources, such as work social support, and personal resources, such as an internal locus of control, may help DCWs perceive work overload and other work-related stressors as less threatening and galvanize them to cope more effectively to prevent burnout. However, little is known about what resources are effective for coping with what types of work stress. Thus, we examined how work stress and social and personal resources are associated with burnout for DCWs. We conducted a survey of DCWs (n = 323) from five community-based organizations that provide residential, vocational, and personal care services for adults with intellectual and developmental disabilities. Participants completed a self-administered survey about their perceptions of work stress, work social support, locus of control, and burnout relative to their daily work routine. We conducted multiple regression analysis to test both the main and interaction effects of work stress and resources with respect to burnout. Work stress, specifically work overload, limited participation decision-making, and client disability care was positively associated with burnout (p < .001). The association between work social support and burnout depended on the levels of work overload (p < .05), and the association between locus of control and burnout depended on the levels of work overload (p < .05) and participation in decision-making (p < .05). Whether work social support and locus of control make a difference depends on the kinds and the levels of work stressors. The findings underscore the importance of strong work-based social support networks and stress management resources for DCWs. PMID:21316918

Significant Locus and Metabolic Genetic Correlations Revealed in Genome-Wide Association Study of Anorexia Nervosa.

PubMed

Duncan, Laramie; Yilmaz, Zeynep; Gaspar, Helena; Walters, Raymond; Goldstein, Jackie; Anttila, Verneri; Bulik-Sullivan, Brendan; Ripke, Stephan; Thornton, Laura; Hinney, Anke; Daly, Mark; Sullivan, Patrick F; Zeggini, Eleftheria; Breen, Gerome; Bulik, Cynthia M

2017-09-01

The authors conducted a genome-wide association study of anorexia nervosa and calculated genetic correlations with a series of psychiatric, educational, and metabolic phenotypes. Following uniform quality control and imputation procedures using the 1000 Genomes Project (phase 3) in 12 case-control cohorts comprising 3,495 anorexia nervosa cases and 10,982 controls, the authors performed standard association analysis followed by a meta-analysis across cohorts. Linkage disequilibrium score regression was used to calculate genome-wide common variant heritability (single-nucleotide polymorphism [SNP]-based heritability [h 2 SNP ]), partitioned heritability, and genetic correlations (r g ) between anorexia nervosa and 159 other phenotypes. Results were obtained for 10,641,224 SNPs and insertion-deletion variants with minor allele frequencies >1% and imputation quality scores >0.6. The h 2 SNP of anorexia nervosa was 0.20 (SE=0.02), suggesting that a substantial fraction of the twin-based heritability arises from common genetic variation. The authors identified one genome-wide significant locus on chromosome 12 (rs4622308) in a region harboring a previously reported type 1 diabetes and autoimmune disorder locus. Significant positive genetic correlations were observed between anorexia nervosa and schizophrenia, neuroticism, educational attainment, and high-density lipoprotein cholesterol, and significant negative genetic correlations were observed between anorexia nervosa and body mass index, insulin, glucose, and lipid phenotypes. Anorexia nervosa is a complex heritable phenotype for which this study has uncovered the first genome-wide significant locus. Anorexia nervosa also has large and significant genetic correlations with both psychiatric phenotypes and metabolic traits. The study results encourage a reconceptualization of this frequently lethal disorder as one with both psychiatric and metabolic etiology.

ELM: AN ALGORITHM TO ESTIMATE THE ALPHA ABUNDANCE FROM LOW-RESOLUTION SPECTRA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bu, Yude; Zhao, Gang; Kumar, Yerra Bharat

We have investigated a novel methodology using the extreme learning machine (ELM) algorithm to determine the α abundance of stars. Applying two methods based on the ELM algorithm—ELM+spectra and ELM+Lick indices—to the stellar spectra from the ELODIE database, we measured the α abundance with a precision better than 0.065 dex. By applying these two methods to the spectra with different signal-to-noise ratios (S/Ns) and different resolutions, we found that ELM+spectra is more robust against degraded resolution and ELM+Lick indices is more robust against variation in S/N. To further validate the performance of ELM, we applied ELM+spectra and ELM+Lick indices to SDSSmore » spectra and estimated α abundances with a precision around 0.10 dex, which is comparable to the results given by the SEGUE Stellar Parameter Pipeline. We further applied ELM to the spectra of stars in Galactic globular clusters (M15, M13, M71) and open clusters (NGC 2420, M67, NGC 6791), and results show good agreement with previous studies (within 1σ). A comparison of the ELM with other widely used methods including support vector machine, Gaussian process regression, artificial neural networks, and linear least-squares regression shows that ELM is efficient with computational resources and more accurate than other methods.« less

Academic Procrastination: The Relationship Between Causal Attribution Styles and Behavioral Postponement

PubMed Central

Badri Gargari, Rahim; Sabouri, Hossein; Norzad, Fatemeh

2011-01-01

Objective: This research was conducted to study the relationship between attribution and academic procrastination in University Students. Methods: The subjects were 203 undergraduate students, 55 males and 148 females, selected from English and French language and literature students of Tabriz University. Data were gathered through Procrastination Assessment Scale-student (PASS) and Causal Dimension Scale (CDA) and were analyzed by multiple regression analysis (stepwise). Results: The results showed that there was a meaningful and negative relation between the locus of control and controllability in success context and academic procrastination. Besides, a meaningful and positive relation was observed between the locus of control and stability in failure context and procrastination. It was also found that 17% of the variance of procrastination was accounted by linear combination of attributions. Conclusion: We believe that causal attribution is a key in understanding procrastination in academic settings and is used by those who have the knowledge of Causal Attribution styles to organize their learning. PMID:24644450

A Control-Based Multidimensional Approach to the Role of Optimism in the Use of Dementia Day Care Services.

PubMed

Contador, Israel; Fernández-Calvo, Bernardino; Palenzuela, David L; Campos, Francisco Ramos; Rivera-Navarro, Jesús; de Lucena, Virginia Menezes

2015-11-01

We examined whether grounded optimism and external locus of control are associated with admission to dementia day care centers (DCCs). A total of 130 informal caregivers were recruited from the Alzheimer's Association in Salamanca (northwest Spain). All caregivers completed an assessment protocol that included the Battery of Generalized Expectancies of Control Scales (BEEGC-20, acronym in Spanish) as well as depression and burden measures. The decision of the care setting at baseline assessment (own home vs DCC) was considered the main outcome measure in the logistic regression analyses. Grounded optimism was a preventive factor for admission (odds ratio [OR]: 0.34 and confidence interval [CI]: 0.15-0.75), whereas external locus of control (OR: 2.75, CI: 1.25-6.03) increased the probabilities of using DCCs. Depression mediated the relationship between optimism and DCCs, but this effect was not consistent for burden. Grounded optimism promotes the extension of care at home for patients with dementia. © The Author(s) 2013.

pKWmEB: integration of Kruskal-Wallis test with empirical Bayes under polygenic background control for multi-locus genome-wide association study.

PubMed

Ren, Wen-Long; Wen, Yang-Jun; Dunwell, Jim M; Zhang, Yuan-Ming

2018-03-01

Although nonparametric methods in genome-wide association studies (GWAS) are robust in quantitative trait nucleotide (QTN) detection, the absence of polygenic background control in single-marker association in genome-wide scans results in a high false positive rate. To overcome this issue, we proposed an integrated nonparametric method for multi-locus GWAS. First, a new model transformation was used to whiten the covariance matrix of polygenic matrix K and environmental noise. Using the transferred model, Kruskal-Wallis test along with least angle regression was then used to select all the markers that were potentially associated with the trait. Finally, all the selected markers were placed into multi-locus model, these effects were estimated by empirical Bayes, and all the nonzero effects were further identified by a likelihood ratio test for true QTN detection. This method, named pKWmEB, was validated by a series of Monte Carlo simulation studies. As a result, pKWmEB effectively controlled false positive rate, although a less stringent significance criterion was adopted. More importantly, pKWmEB retained the high power of Kruskal-Wallis test, and provided QTN effect estimates. To further validate pKWmEB, we re-analyzed four flowering time related traits in Arabidopsis thaliana, and detected some previously reported genes that were not identified by the other methods.

Effect of HLA-C and DQ matching on Pediatric Heart Transplant Graft Survival

PubMed Central

Butts, Ryan J.; Savage, Andrew J.; Nietert, Paul J.; Kavarana, Minoo; Moussa, Omar; Burnette, Ali L.; Atz, Andrew M.

2014-01-01

Background Higher degree of HLA matching at the A, B, and DR-loci has been associated with improved long-term survival after pediatric heart transplantation in multiple ISHLT registry reports. The aim of this study was to investigate the association of HLA matching at the C and DQ loci with pediatric graft survival. Methods The UNOS database was queried for isolated heart transplants that occurred from 1988 to 2012 with a recipient age of 17 or less and at least one postoperative follow up encounter. When analyzing HLA matching at the C or DQ loci, only those transplants with complete typing of donor and recipient at the respective loci were included. Transplants were divided into patients with at least one match at the C-locus (C-match) versus no match (C-no), and at least one match at the DQ locus versus no match (DQ-match versus DQ-no). Primary outcome was graft loss. Univariate analysis was performed with log-rank test. Cox regression analysis was performed with following patient factors included in the model: recipient age, ischemic time; recipient on ventilator, ECMO, ventricular assist device or inotropes at transplant; recipient serum bilirubin and creatinine closest to transplant, donor-recipient weight ratio, underlying cardiac diagnosis, crossmatch results, transplant year, and HLA matching at the A, B, and DR loci. Results Complete typing at the C-locus occurred in 2429/4731 (51%) transplants and 3498/4731 (74%) transplants had complete typing at the DQ locus. C-match did not differ from C-no with respect to patient factors, except for year of transplant; [C-match median year 2007 (IQR 1997–2010) vs. C-no median year 2005 (IQR 1996–2009), p=0.03] and degree of HLA matching at A, B, and DR loci (11.9% of C-match with high level of HLA matching v. 3% of C-no, p<0.01). Matching at the C-locus was not associated with decreased risk of graft loss [C-no median graft survival 13.1 yrs (95%CI 11.5–14.8) vs. C-match 15.1 yrs (95%CI 13.5–16.6) p=0.44, log-rank, hazard ratio 0.93 (95%CI 0.76–1.15, p=0.52)]. DQ-match did not differ from DQ-no in any of the above-mentioned patient factors, except DQ-match was more likely to have high degree of matching at the A, B, and DR loci versus DQ-no (9.8% v. 3.2%, p<0.01). Matching at the DQ-locus was not associated with decreased risk of graft loss [DQ-no median graft survival 13.1yrs (95%CI 11.7–14.6) vs. DQ-match 13.0 yrs (11.4–14.6) p=0.80, log rank, hazard ratio 0.95 (0.81–1.1), p=0.51]. Conclusion Complete typing at the C-locus of both donor and recipient occurs less often then typing at the DQ locus. A higher degree of donor-recipient HLA matching at the C-locus or the DQ-locus appears not to confer any graft survival advantage. PMID:25128416

Effect of human leukocyte antigen-C and -DQ matching on pediatric heart transplant graft survival.

PubMed

Butts, Ryan J; Savage, Andrew J; Nietert, Paul J; Kavarana, Minoo; Moussa, Omar; Burnette, Ali L; Atz, Andrew M

2014-12-01

A higher degree of human leukocyte antigen (HLA) matching at the A, B, and DR loci has been associated with improved long-term survival after pediatric heart transplantation in multiple International Society for Heart and Lung Transplantation registry reports. The aim of this study was to investigate the association of HLA matching at the C and DQ loci with pediatric graft survival. The United Network of Organ Sharing database was queried for isolated heart transplants that occurred from 1988 to 2012 with a recipient age of 17 or younger and at least 1 postoperative follow-up encounter. When HLA matching at the C or DQ loci were analyzed, only transplants with complete typing of donor and recipient at the respective loci were included. Transplants were divided into patients with at least 1 match at the C locus (C-match) vs no match (C-no), and at least 1 match at the DQ (DQ-match) locus vs no match (DQ-no). Primary outcome was graft loss. Univariate analysis was performed with the log-rank test. Cox regression analysis was performed with the following patient factors included in the model: recipient age, ischemic time; recipient on ventilator, extracorporeal membrane oxygenation, ventricular assist device, or inotropes at transplant; recipient serum bilirubin and creatinine closest to transplant, ratio of donor weight to recipient weight, underlying cardiac diagnosis, crossmatch results, transplant year, and HLA matching at the A, B, and DR loci. Complete typing at the C locus occurred in 2,429 of 4,731 transplants (51%), and complete typing at the DQ locus occurred in 3,498 of 4,731 transplants (74%). Patient factors were similar in C-match and C-no, except for year of transplant (median year, 2007 [interquartile range, 1997-2010] vs year 2005 [interquartile range, 1996-2009], respectively; p = 0.03) and the degree of HLA matching at the A, B, and DR loci (high level of HLA matching in 11.9% vs 3%, respectively; p < 0.01). Matching at the C locus was not associated with a decreased risk of graft loss (median graft survival: 13.1 years [95% confidence interval {CI}, 11.5-14.8] in C-no vs 15.1 years [95% CI, 13.5-16.6) in C-match, p = 0.44 log-rank; hazard ratio, 0.93; 95% CI, 0.76-1.15; p = 0.52). DQ-match did not differ from DQ-no in any of the analyzed patient factors, except DQ-match was more likely to have high degree of matching at the A, B, and DR loci vs DQ-no (9.8% vs 3.2%, p < 0.01). Matching at the DQ locus was not associated with decreased risk of graft loss (median graft survival: DQ-no, 13.1 years [95% CI, 11.7-14.6) vs DQ-match, 13.0 years [95% CI, 11.4-14.6], p = 0.80, log-rank; hazard ratio, 0.95; 95% CI, 0.81-1.1; p = 0.51. Complete typing at the C locus of both donor and recipient occurs less often then typing at the DQ locus. A higher degree of donor-recipient HLA matching at the C locus or the DQ locus appears not to confer any graft survival advantage. Copyright © 2014 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

Improvement on Exoplanet Detection Methods and Analysis via Gaussian Process Fitting Techniques

NASA Astrophysics Data System (ADS)

Van Ross, Bryce; Teske, Johanna

2018-01-01

Planetary signals in radial velocity (RV) data are often accompanied by signals coming solely from stellar photo- or chromospheric variation. Such variation can reduce the precision of planet detection and mass measurements, and cause misidentification of planetary signals. Recently, several authors have demonstrated the utility of Gaussian Process (GP) regression for disentangling planetary signals in RV observations (Aigrain et al. 2012; Angus et al. 2017; Czekala et al. 2017; Faria et al. 2016; Gregory 2015; Haywood et al. 2014; Rajpaul et al. 2015; Foreman-Mackey et al. 2017). GP models the covariance of multivariate data to make predictions about likely underlying trends in the data, which can be applied to regions where there are no existing observations. The potency of GP has been used to infer stellar rotation periods; to model and disentangle time series spectra; and to determine physical aspects, populations, and detection of exoplanets, among other astrophysical applications. Here, we implement similar analysis techniques to times series of the Ca-2 H and K activity indicator measured simultaneously with RVs in a small sample of stars from the large Keck/HIRES RV planet search program. Our goal is to characterize the pattern(s) of non-planetary variation to be able to know what is/ is not a planetary signal. We investigated ten different GP kernels and their respective hyperparameters to determine the optimal combination (e.g., the lowest Bayesian Information Criterion value) in each stellar data set. To assess the hyperparameters’ error, we sampled their posterior distributions using Markov chain Monte Carlo (MCMC) analysis on the optimized kernels. Our results demonstrate how GP analysis of stellar activity indicators alone can contribute to exoplanet detection in RV data, and highlight the challenges in applying GP analysis to relatively small, irregularly sampled time series.

Statistics and Machine Learning based Outlier Detection Techniques for Exoplanets

NASA Astrophysics Data System (ADS)

Goel, Amit; Montgomery, Michele

2015-08-01

Architectures of planetary systems are observable snapshots in time that can indicate formation and dynamic evolution of planets. The observable key parameters that we consider are planetary mass and orbital period. If planet masses are significantly less than their host star masses, then Keplerian Motion is defined as P^2 = a^3 where P is the orbital period in units of years and a is the orbital period in units of Astronomical Units (AU). Keplerian motion works on small scales such as the size of the Solar System but not on large scales such as the size of the Milky Way Galaxy. In this work, for confirmed exoplanets of known stellar mass, planetary mass, orbital period, and stellar age, we analyze Keplerian motion of systems based on stellar age to seek if Keplerian motion has an age dependency and to identify outliers. For detecting outliers, we apply several techniques based on statistical and machine learning methods such as probabilistic, linear, and proximity based models. In probabilistic and statistical models of outliers, the parameters of a closed form probability distributions are learned in order to detect the outliers. Linear models use regression analysis based techniques for detecting outliers. Proximity based models use distance based algorithms such as k-nearest neighbour, clustering algorithms such as k-means, or density based algorithms such as kernel density estimation. In this work, we will use unsupervised learning algorithms with only the proximity based models. In addition, we explore the relative strengths and weaknesses of the various techniques by validating the outliers. The validation criteria for the outliers is if the ratio of planetary mass to stellar mass is less than 0.001. In this work, we present our statistical analysis of the outliers thus detected.

The ESR1 (6q25) Locus Is Associated with Calcaneal Ultrasound Parameters and Radial Volumetric Bone Mineral Density in European Men

PubMed Central

Thomson, Wendy; Boonen, Steven; Borghs, Herman; Vanderschueren, Dirk; Gielen, Evelien; Huhtaniemi, Ilpo T.; Adams, Judith E.; Ward, Kate A.; Bartfai, Gyorgy; Casanueva, Felipe; Finn, Joseph D.; Forti, Gianni; Giwercman, Aleksander; Han, Thang S.; Kula, Krzysztof; Labrie, Fernand; Lean, Michael E. J.; Pendleton, Neil; Punab, Margus; Wu, Frederick C. W.; O'Neill, Terence W.

2011-01-01

Purpose Genome-wide association studies (GWAS) have identified 6q25, which incorporates the oestrogen receptor α gene (ESR1), as a quantitative trait locus for areal bone mineral density (BMDa) of the hip and lumbar spine. The aim of this study was to determine the influence of this locus on other bone health outcomes; calcaneal ultrasound (QUS) parameters, radial peripheral quantitative computed tomography (pQCT) parameters and markers of bone turnover in a population sample of European men. Methods Eight single nucleotide polymorphisms (SNP) in the 6q25 locus were genotyped in men aged 40–79 years from 7 European countries, participating in the European Male Ageing Study (EMAS). The associations between SNPs and measured bone parameters were tested under an additive genetic model adjusting for centre using linear regression. Results 2468 men, mean (SD) aged 59.9 (11.1) years had QUS measurements performed and bone turnover marker levels measured. A subset of 628 men had DXA and pQCT measurements. Multiple independent SNPs showed significant associations with BMD using all three measurement techniques. Most notably, rs1999805 was associated with a 0.10 SD (95%CI 0.05, 0.16; p = 0.0001) lower estimated BMD at the calcaneus, a 0.14 SD (95%CI 0.05, 0.24; p = 0.004) lower total hip BMDa, a 0.12 SD (95%CI 0.02, 0.23; p = 0.026) lower lumbar spine BMDa and a 0.18 SD (95%CI 0.06, 0.29; p = 0.003) lower trabecular BMD at the distal radius for each copy of the minor allele. There was no association with serum levels of bone turnover markers and a single SNP which was associated with cortical density was also associated with cortical BMC and thickness. Conclusions Our data replicate previous associations found between SNPs in the 6q25 locus and BMDa at the hip and extend these data to include associations with calcaneal ultrasound parameters and radial volumetric BMD. PMID:21760950

Disparities in Oral Health Behaviour among Young Adults in Mangalore, India: A Psychosocial Perspective.

PubMed

Rajesh, G; Seemanthini, Simi; Naik, Dilip; Pai, Keshava; Rao, Ashwini

2017-04-01

Oral health inequalities imply unequal distribution of health and disease across socioeconomic gradients. Oral health related behaviour and its psychosocial antecedents can have a major impact on oral disease pathways in communities. To ascertain disparities in oral health behaviour and its psychosocial antecedents among young adults in Mangalore, Karnataka, India. Present study was carried out among 341 degree students at three randomly chosen institutions belonging to government, aided and private colleges in Mangalore. Oral health behaviour was assessed by a structured, pre-tested, self-administered questionnaire. Information about oral hygiene habits, tobacco use, sugar consumption, dental attendance patterns were collected. Respondent's self-reported gingivitis, perceived general and oral health, perceived need for care and locus of control were assessed. Information about demographic details was collected. Correlation analysis employed Pearson's correlation coefficient and binary logistic regression analysis was employed with snacking as dependent variable. Twice daily brushing was significantly associated with gender (r=0.142, p=0.009), type of college (r=-0.164, p=0.003) and father's occupation (r=0.107, p=0.049), while tobacco use was significantly associated with gender (r=0.284, p=0.000), religion (r=-0.234, p=0.000), type of college (r=0.312, p=0.000), father's education (r=0.130, p=0.017) and occupation (r=0.120, p=0.027). Self-perceived oral health was significantly associated with snacking (r=0.173, p=0.001) and tobacco use (r=-0.261, p=0.000), while locus of control was associated with snacking (r=0.140, p=0.009). Regression analysis revealed that father's education (OR=0.399, p=0.014), self-perceived need for care (OR=0.354, p=0.009), and locus of control (OR=0.166, p=0.003) emerged as significant predictors of snacking behaviour. Psychosocial antecedents were significantly associated with oral health behaviour among the respondents. Policy and decision makers should consider causes of causes while tackling oral health problems. Present study may contribute towards addressing oral health inequalities in developing nations, where oral health issues are compounded by a definite paucity of resources.

CREB1 is a strong genetic predictor of the variation in exercise heart rate response to regular exercise: the HERITAGE Family Study.

PubMed

Rankinen, Tuomo; Argyropoulos, George; Rice, Treva; Rao, D C; Bouchard, Claude

2010-06-01

A genome-wide linkage scan identified a quantitative trait locus for exercise training-induced changes in submaximal exercise (50 W) heart rate (DeltaHR50) on chromosome 2q33.3-q34 in the HERITAGE Family Study (n=472). To fine-map the region, 1450 tag SNPs were genotyped between 205 and 215 Mb on chromosome 2. The strongest evidence of association with DeltaHR50 was observed with 2 single-nucleotide polymorphisms (SNPs) located in the 5' region of the cAMP-responsive element-binding protein 1 (CREB1) gene (rs2253206: P=1.6x10(-5) and rs2360969: P=4.3x10(-5)). The associations remained significant (P=0.01 and P=0.023, respectively) after accounting for multiple testing. Regression modeling of the 39 most significant SNPs in the single-SNP analysis identified 9 SNPs that collectively explained 20% of the DeltaHR50 variance. CREB1 SNP rs2253206 had the strongest effect (5.45% of variance), followed by SNPs in the FASTKD2 (3.1%), MAP2 (2.6%), SPAG16 (2.1%), ERBB4 (3 SNPs approximately 1.4% each), IKZF2 (1.4%), and PARD3B (1.0%) loci. In conditional linkage analysis, 6 SNPs from the final regression model (CREB1, FASTKD2, MAP2, ERBB4, IKZF2, and PARD3B) accounted for the original linkage signal: The log of the odds score dropped from 2.10 to 0.41 after adjusting for all 6 SNPs. Functional studies revealed that the common allele of rs2253206 exhibits significantly (P<0.05) lower promoter activity than the minor allele. Our data suggest that functional DNA sequence variation in the CREB1 locus is strongly associated with DeltaHR50 and explains a considerable proportion of the quantitative trait locus variance. However, at least 5 additional SNPs seem to be required to fully account for the original linkage signal.

Model Atmospheres for Massive Gas Giants with Thick Clouds: Application to the HR 8799 Planets and Predictions for Future Detections

NASA Astrophysics Data System (ADS)

Madhusudhan, Nikku; Burrows, Adam; Currie, Thayne

2011-08-01

We have generated an extensive new suite of massive giant planet atmosphere models and used it to obtain fits to photometric data for the planets HR 8799b, c, and d. We consider a wide range of cloudy and cloud-free models. The cloudy models incorporate different geometrical and optical thicknesses, modal particle sizes, and metallicities. For each planet and set of cloud parameters, we explore grids in gravity and effective temperature, with which we determine constraints on the planet's mass and age. Our new models yield statistically significant fits to the data, and conclusively confirm that the HR 8799 planets have much thicker clouds than those required to explain data for typical L and T dwarfs. Both models with (1) physically thick forsterite clouds and a 60 μm modal particle size and (2) clouds made of 1 μm sized pure iron droplets and 1% supersaturation fit the data. Current data are insufficient to accurately constrain the microscopic cloud properties, such as composition and particle size. The range of best-estimated masses for HR 8799b, HR 8799c, and HR 8799d conservatively span 2-12 MJ , 6-13 MJ , and 3-11 MJ , respectively, and imply coeval ages between ~10 and ~150 Myr, consistent with previously reported stellar ages. The best-fit temperatures and gravities are slightly lower than values obtained by Currie et al. using even thicker cloud models. Finally, we use these models to predict the near-to-mid-IR colors of soon-to-be imaged planets. Our models predict that planet-mass objects follow a locus in some near-to-mid-IR color-magnitude diagrams that is clearly separable from the standard L/T dwarf locus for field brown dwarfs.

The FTO gene polymorphism (rs9939609) is associated with metabolic syndrome in morbidly obese subjects from southern Italy.

PubMed

Liguori, Rosario; Labruna, Giuseppe; Alfieri, Andreina; Martone, Domenico; Farinaro, Eduardo; Contaldo, Franco; Sacchetti, Lucia; Pasanisi, Fabrizio; Buono, Pasqualina

2014-08-01

Gene variants in MC4R, SIRT1 and FTO are associated with severe obesity and metabolic impairment in Caucasians. We investigated whether common variants in these genes are associated with metabolic syndrome (MetS) in a large group of morbidly obese young adults from southern Italy. One thousand morbidly obese subjects (62% women, mean body mass index 46.5 kg/m(2), mean age 32.6 years) whose families had lived in southern Italy for at least 2 generations were recruited. Single-nucleotide polymorphisms (SNPs) rs12970134, rs477181, rs502933 (MC4R locus), rs3818292, rs7069102, rs730821, rs2273773, rs12413112 (SIRT1 locus) and rs1421085, rs9939609, 9930506, 1121980 (FTO locus) were genotyped by Taqman assay; blood parameters were assayed by routine methods; the Fat Mass, Fat Free Mass, Respiratory Quotient, Basal Metabolic Rate (BMR) and waist circumference were also determined. Binomial logistic regression showed that the TA heterozygous genotype of SNP rs9939609 in the FTO gene was associated with the presence of MetS in our population [OR (95% CI): 2.53 (1.16-5.55)]. Furthermore, the FTO rs9939609 genotype accounted for 21.3% of the MetS phenotype together with total cholesterol, BMR and age. Our results extend the knowledge on genotype susceptibility for MetS in relation to a specific geographical area of residence. Copyright © 2014 Elsevier Ltd. All rights reserved.

Mosfire Spectroscopy Of Galaxies In Cosmic Noon

NASA Astrophysics Data System (ADS)

Nanayakkara, Themiya

2017-07-01

The recent development of sensitive, multiplexed near infra-red instruments has presented astronomers the unique opportunity to survey mass/magnitude complete samples of galaxies at Cosmic Noon, a time period where ˜ 80% of the observed baryonic mass is generated and galaxies are actively star-forming and evolving rapidly. This thesis takes advantage of the recently commissioned MOSFIRE spectrograph on Keck, to conduct a survey (ZFIRE) of galaxies at 1.5 < z < 2.5 to measure accurate spectroscopic redshifts and basic galaxy properties derived from multiple emission lines. The majority of the thesis work involved survey planning, observing, data reduction, and catalogue preparation of the ZFIRE survey and is described in detail in this thesis. Using the ZFIRE spectroscopic redshifts, I show why spectroscopy is instrumental to determine fundamental galaxy properties via SED fitting techniques and to probe gravitationally bound structures in the early universe. The thesis further presents basic properties of the ZFIRE data products publicly released for the benefit of the astronomy community. The high mass-completeness of the ZFIRE spectroscopic data at z ˜ 2 makes it ideal to study fundamental galaxy properties such as, star formation rates, metallicities, interstellar medium properties, galaxy kinematics, and the stellar initial mass functions in unbiased star-forming galaxies. This thesis focuses on one such aspect, the IMF. By using a mass-complete (log10(M∗/M) ˜ 9.3) sample of 102 galaxies at z = 2.1 in the COSMOS field from ZFIRE, I investigate the IMF of star-forming galaxies by revisiting the classical Kennicutt (1983) technique of using the Hα equivalent widths and rest-frame optical colours. I present a thorough analysis of stellar population properties of the ZFIRE sample via multiple synthetic stellar population models and stellar libraries. Due to an excess of high Hα-EW galaxies that are up to 0.3-0.5 dex above the Salpeter locus, the Hα-EW distribution is much broader (10-500˚A) than can be explained by a simple monotonic SFH with a standard Salpeter-slope IMF. This result is robust against uncertainties in dust correction and observational bias, and no single IMF (i.e. non-Salpeter slope) can explain the distribution. Starburst models cannot explain the Hα-EW distribution because: 1) spectral stacking still shows an excess Hα-EW in composite populations and 2) Monte Carlo burst models show that the timescale for high Hα-EW is too short to explain their abundance in the ZFIRE sample. Other possible physical mechanisms that could produce excess ionising photons for a given star-formation rate, and hence high equivalent widths, including models with variations in stellar rotation, binary star evolution, metallicity, and upper mass cutoff of the IMF are investigated and ruled out. IMF variation is one possible explanation for the high Hα-EWs. However, the highest Hα-EW values would require very shallow slopes (Γ > -1.0) and no single IMF change can explain the large variation in Hα-EWs. Instead the IMF would have to vary stochastically. Therefore, currently there is no simple physical model to explain the large variation in Hα-EWs at z ˜ 2, but the distinct differences of the z ˜ 2 sample with that of local galaxies are found to be intriguing. Further study is required to fully constrain the stellar population parameters of actively star-forming galaxies at the epoch of maximum star-formation. Probing multiple rest-frame UV and optical features of galaxies simultaneously along with galaxy dynamical studies via integral field spectroscopy will be vital to understand stellar and ionized gas properties of these galaxies. Furthermore, low-z analogues of galaxies at z ˜ 2 will provide vital clues to constrain galaxy evolution models aided by the ability to probe galaxies in high resolution to low surface brightness limits.

Kepler AutoRegressive Planet Search

NASA Astrophysics Data System (ADS)

Caceres, Gabriel Antonio; Feigelson, Eric

2016-01-01

The Kepler AutoRegressive Planet Search (KARPS) project uses statistical methodology associated with autoregressive (AR) processes to model Kepler lightcurves in order to improve exoplanet transit detection in systems with high stellar variability. We also introduce a planet-search algorithm to detect transits in time-series residuals after application of the AR models. One of the main obstacles in detecting faint planetary transits is the intrinsic stellar variability of the host star. The variability displayed by many stars may have autoregressive properties, wherein later flux values are correlated with previous ones in some manner. Our analysis procedure consisting of three steps: pre-processing of the data to remove discontinuities, gaps and outliers; AR-type model selection and fitting; and transit signal search of the residuals using a new Transit Comb Filter (TCF) that replaces traditional box-finding algorithms. The analysis procedures of the project are applied to a portion of the publicly available Kepler light curve data for the full 4-year mission duration. Tests of the methods have been made on a subset of Kepler Objects of Interest (KOI) systems, classified both as planetary `candidates' and `false positives' by the Kepler Team, as well as a random sample of unclassified systems. We find that the ARMA-type modeling successfully reduces the stellar variability, by a factor of 10 or more in active stars and by smaller factors in more quiescent stars. A typical quiescent Kepler star has an interquartile range (IQR) of ~10 e-/sec, which may improve slightly after modeling, while those with IQR ranging from 20 to 50 e-/sec, have improvements from 20% up to 70%. High activity stars (IQR exceeding 100) markedly improve. A periodogram based on the TCF is constructed to concentrate the signal of these periodic spikes. When a periodic transit is found, the model is displayed on a standard period-folded averaged light curve. Our findings to date on real-data tests of the KARPS methodology will be discussed including confirmation of some Kepler Team `candidate' planets. We also present cases of new possible planetary signals.

The PILI@Work Program: a translation of the diabetes prevention program to Native Hawaiian-serving worksites in Hawai'i.

PubMed

Townsend, Claire K M; Miyamoto, Robin E S; Antonio, Mapuana; Zhang, Guangxing; Paloma, Diane; Basques, DeAnna; Braun, Kathryn L; Kaholokula, Joseph Keawe'aimoku

2016-06-01

A previously translated Diabetes Prevention Program Lifestyle Intervention (DPP-LI) was adapted for delivery as a worksite-based intervention, called PILI@Work, to address obesity disparities in Native Hawaiians/Pacific Islanders. This study examined the effectiveness of PILI@Work and factors associated with weight loss at post-intervention. Overweight/obese employees of 15 Native Hawaiian-serving organizations received the 3-month component of PILI@Work. Assessments included weight, systolic/diastolic blood pressure, physical activity and functioning, fat intake, locus of weight control, social support, and self-efficacy. Weight, systolic/diastolic blood pressure, physical functioning, physical activity frequency, fat intake, family support, and eating self-efficacy improved from pre- to post-intervention. Regression analysis indicated that worksite type, decreased diastolic blood pressure, increased physical activity, and more internalized locus of weight control were significantly associated with 3-month weight loss. PILI@Work initiated weight loss in Native Hawaiians/Pacific Islanders. DPP-LI translated to worksite settings and tailored for specific populations can be effective for addressing obesity.

Genetic aspect of Alzheimer disease: Results of complex segregation analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sadonvick, A.D.; Lee, I.M.L.; Bailey-Wilson, J.E.

1994-09-01

The study was designed to evaluate the possibility that a single major locus will explain the segregation of Alzheimer disease (AD). The data were from the population-based AD Genetic Database and consisted of 402 consecutive, unrelated probands, diagnosed to have either `probable` or `autopsy confirmed` AD and their 2,245 first-degree relatives. In this analysis, a relative was considered affected with AD only when there were sufficient medical/autopsy data to support diagnosis of AD being the most likely cause of the dementia. Transmission probability models allowing for a genotype-dependent and logistically distributed age-of-onset were used. The program REGTL in the S.A.G.E.more » computer program package was used for a complex segregation analysis. The models included correction for single ascertainment. Regressive familial effects were not estimated. The data were analyzed to test for single major locus (SML), random transmission and no transmission (environmental) hypotheses. The results of the complex segregation analysis showed that (1) the SML was the best fit, and (2) the non-genetic models could be rejected.« less

Constraints on the Dynamical Environments of Supermassive Black-Hole Binaries Using Pulsar-Timing Arrays.

PubMed

Taylor, Stephen R; Simon, Joseph; Sampson, Laura

2017-05-05

We introduce a technique for gravitational-wave analysis, where Gaussian process regression is used to emulate the strain spectrum of a stochastic background by training on population-synthesis simulations. This leads to direct Bayesian inference on astrophysical parameters. For pulsar timing arrays specifically, we interpolate over the parameter space of supermassive black-hole binary environments, including three-body stellar scattering, and evolving orbital eccentricity. We illustrate our approach on mock data, and assess the prospects for inference with data similar to the NANOGrav 9-yr data release.

Stereotype contrast effect on neuropsychological assessment of contact-sport players: The moderating role of locus of control.

PubMed

Fresson, Megan; Dardenne, Benoit; Geurten, Marie; Meulemans, Thierry

2017-11-01

Diagnosis threat has been shown to produce detrimental effects on neuropsychological performance in individuals with mild traumatic brain injury (mTBI). Focusing on contact-sport players who are at great risk of mTBI, our study was designed to examine the moderating role of internal locus of control. Specifically, we predicted that following diagnosis threat (reminder of their risk of sustaining mTBI and of its consequences), low-internal contact-sport players would underperform (assimilation to the stereotype), while their high-internal counterparts would outperform (contrast effect). We predicted that effort and anxiety would mediate these effects. Contact-sport players and non-contact-sport players ("control" group) were randomly assigned to one condition (diagnosis threat or neutral) and then completed attention, executive, episodic memory, and working memory tasks. Regarding mediating and moderating variables, participants rated their effort and anxiety (self-report measures) and completed the Levenson (1974) locus of control scale. Regression-based path analyses were carried out to examine the direct and indirect effects. As expected, there was no effect of condition on the control group's performance. Contact-sport players with moderate and high levels of internal control outperformed (contrast effect) on executive and episodic memory tasks following diagnosis threat compared to the neutral condition. Additionally, the less anxiety moderate- and high-internal contact-sport participants felt, the better they performed on episodic memory and executive tasks. However, contact-sport players low in internal control did not underperform (assimilation effect) under diagnosis threat. Our results suggest that diagnosis threat instructions may have challenged moderate- and high-internal contact-sport participants, leading them to outperform compared to the neutral condition. Individuals who have moderate and high levels of internal locus of control may have higher performance under diagnosis threat compared to the neutral condition because of their feeling of control over their cognitive performance.

Fine-mapping diabetes-related traits, including insulin resistance, in heterogeneous stock rats

PubMed Central

Holl, Katie L.; Oreper, Daniel; Xie, Yuying; Tsaih, Shirng-Wern; Valdar, William

2012-01-01

Type 2 diabetes (T2D) is a disease of relative insulin deficiency resulting from both insulin resistance and beta cell failure. We have previously used heterogeneous stock (HS) rats to fine-map a locus for glucose tolerance. We show here that glucose intolerance in the founder strains of the HS colony is mediated by different mechanisms: insulin resistance in WKY and an insulin secretion defect in ACI, and we demonstrate a high degree of variability for measures of insulin resistance and insulin secretion in HS rats. As such, our goal was to use HS rats to fine-map several diabetes-related traits within a region on rat chromosome 1. We measured blood glucose and plasma insulin levels after a glucose tolerance test in 782 male HS rats. Using 97 SSLP markers, we genotyped a 68 Mb region on rat chromosome 1 previously implicated in glucose and insulin regulation. We used linkage disequilibrium mapping by mixed model regression with inferred descent to identify a region from 198.85 to 205.9 that contains one or more quantitative trait loci (QTL) for fasting insulin and a measure of insulin resistance, the quantitative insulin sensitivity check index. This region also encompasses loci identified for fasting glucose and Insulin_AUC (area under the curve). A separate <3 Mb QTL was identified for body weight. Using a novel penalized regression method we then estimated effects of alternative haplotype pairings under each locus. These studies highlight the utility of HS rats for fine-mapping genetic loci involved in the underlying causes of T2D. PMID:22947656

African Ancestry Analysis and Admixture Genetic Mapping for Proliferative Diabetic Retinopathy in African Americans.

PubMed

Tandon, Arti; Chen, Ching J; Penman, Alan; Hancock, Heather; James, Maurice; Husain, Deeba; Andreoli, Christopher; Li, Xiaohui; Kuo, Jane Z; Idowu, Omolola; Riche, Daniel; Papavasilieou, Evangelia; Brauner, Stacey; Smith, Sataria O; Hoadley, Suzanne; Richardson, Cole; Kieser, Troy; Vazquez, Vanessa; Chi, Cheryl; Fernandez, Marlene; Harden, Maegan; Cotch, Mary Frances; Siscovick, David; Taylor, Herman A; Wilson, James G; Reich, David; Wong, Tien Y; Klein, Ronald; Klein, Barbara E K; Rotter, Jerome I; Patterson, Nick; Sobrin, Lucia

2015-06-01

To examine the relationship between proportion of African ancestry (PAA) and proliferative diabetic retinopathy (PDR) and to identify genetic loci associated with PDR using admixture mapping in African Americans with type 2 diabetes (T2D). Between 1993 and 2013, 1440 participants enrolled in four different studies had fundus photographs graded using the Early Treatment Diabetic Retinopathy Study scale. Cases (n = 305) had PDR while controls (n = 1135) had nonproliferative diabetic retinopathy (DR) or no DR. Covariates included diabetes duration, hemoglobin A1C, systolic blood pressure, income, and education. Genotyping was performed on the Affymetrix platform. The association between PAA and PDR was evaluated using logistic regression. Genome-wide admixture scanning was performed using ANCESTRYMAP software. In the univariate analysis, PDR was associated with increased PAA (odds ratio [OR] = 1.36, 95% confidence interval [CI] = 1.16-1.59, P = 0.0002). In multivariate regression adjusting for traditional DR risk factors, income and education, the association between PAA and PDR was attenuated and no longer significant (OR = 1.21, 95% CI = 0.59-2.47, P = 0.61). For the admixture analyses, the maximum genome-wide score was 1.44 on chromosome 1. In this largest study of PDR in African Americans with T2D to date, an association between PAA and PDR is not present after adjustment for clinical, demographic, and socioeconomic factors. No genome-wide significant locus (defined as having a locus-genome statistic > 5) was identified with admixture analysis. Further analyses with even larger sample sizes are needed to definitively assess if any admixture signal for DR is present.

An Ultra-faint Galaxy Candidate Discovered in Early Data from the Magellanic Satellites Survey

NASA Astrophysics Data System (ADS)

Drlica-Wagner, A.; Bechtol, K.; Allam, S.; Tucker, D. L.; Gruendl, R. A.; Johnson, M. D.; Walker, A. R.; James, D. J.; Nidever, D. L.; Olsen, K. A. G.; Wechsler, R. H.; Cioni, M. R. L.; Conn, B. C.; Kuehn, K.; Li, T. S.; Mao, Y.-Y.; Martin, N. F.; Neilsen, E.; Noel, N. E. D.; Pieres, A.; Simon, J. D.; Stringfellow, G. S.; van der Marel, R. P.; Yanny, B.

2016-12-01

We report a new ultra-faint stellar system found in Dark Energy Camera data from the first observing run of the Magellanic Satellites Survey (MagLiteS). MagLiteS J0644-5953 (Pictor II or Pic II) is a low surface brightness (μ ={28.5}-1+1 {mag} {arcsec}{}-2 within its half-light radius) resolved overdensity of old and metal-poor stars located at a heliocentric distance of {45}-4+5 {kpc}. The physical size ({r}1/2={46}-11+15 {pc} ) and low luminosity ({M}V=-{3.2}-0.5+0.4 {mag} ) of this satellite are consistent with the locus of spectroscopically confirmed ultra-faint galaxies. MagLiteS J0644-5953 (Pic II) is located {11.3}-0.9+3.1 {kpc} from the Large Magellanic Cloud (LMC), and comparisons with simulation results in the literature suggest that this satellite was likely accreted with the LMC. The close proximity of MagLiteS J0644-5953 (Pic II) to the LMC also makes it the most likely ultra-faint galaxy candidate to still be gravitationally bound to the LMC.

The Lowell Observatory Predoctoral Scholar Program

NASA Astrophysics Data System (ADS)

Prato, Lisa; Nofi, Larissa

2018-01-01

Lowell Observatory is pleased to solicit applications for our Predoctoral Scholar Fellowship Program. Now beginning its tenth year, this program is designed to provide unique research opportunities to graduate students in good standing, currently enrolled at Ph.D. granting institutions. Lowell staff research spans a wide range of topics, from astronomical instrumentation, to icy bodies in our solar system, exoplanet science, stellar populations, star formation, and dwarf galaxies. Strong collaborations, the new Ph.D. program at Northern Arizona University, and cooperative links across the greater Flagstaff astronomical community create a powerful multi-institutional locus in northern Arizona. Lowell Observatory's new 4.3 meter Discovery Channel Telescope is operating at full science capacity and boasts some of the most cutting-edge and exciting capabilities available in optical/infrared astronomy. Student research is expected to lead to a thesis dissertation appropriate for graduation at the doctoral level at the student's home institution. For more information, see http://www2.lowell.edu/rsch/predoc.php and links therein. Applications for Fall 2018 are due by May 1, 2018; alternate application dates will be considered on an individual basis.

Quenching or Bursting: Star Formation Acceleration—A New Methodology for Tracing Galaxy Evolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, D. Christopher; Darvish, Behnam; Seibert, Mark

We introduce a new methodology for the direct extraction of galaxy physical parameters from multiwavelength photometry and spectroscopy. We use semianalytic models that describe galaxy evolution in the context of large-scale cosmological simulation to provide a catalog of galaxies, star formation histories, and physical parameters. We then apply models of stellar population synthesis and a simple extinction model to calculate the observable broadband fluxes and spectral indices for these galaxies. We use a linear regression analysis to relate physical parameters to observed colors and spectral indices. The result is a set of coefficients that can be used to translate observedmore » colors and indices into stellar mass, star formation rate, and many other parameters, including the instantaneous time derivative of the star formation rate, which we denote the Star Formation Acceleration (SFA), We apply the method to a test sample of galaxies with GALEX photometry and SDSS spectroscopy, deriving relationships between stellar mass, specific star formation rate, and SFA. We find evidence for a mass-dependent SFA in the green valley, with low-mass galaxies showing greater quenching and higher-mass galaxies greater bursting. We also find evidence for an increase in average quenching in galaxies hosting an active galactic nucleus. A simple scenario in which lower-mass galaxies accrete and become satellite galaxies, having their star-forming gas tidally and/or ram-pressure stripped, while higher-mass galaxies receive this gas and react with new star formation, can qualitatively explain our results.« less

On the Statistical Properties of the Lower Main Sequence

NASA Astrophysics Data System (ADS)

Angelou, George C.; Bellinger, Earl P.; Hekker, Saskia; Basu, Sarbani

2017-04-01

Astronomy is in an era where all-sky surveys are mapping the Galaxy. The plethora of photometric, spectroscopic, asteroseismic, and astrometric data allows us to characterize the comprising stars in detail. Here we quantify to what extent precise stellar observations reveal information about the properties of a star, including properties that are unobserved, or even unobservable. We analyze the diagnostic potential of classical and asteroseismic observations for inferring stellar parameters such as age, mass, and radius from evolutionary tracks of solar-like oscillators on the lower main sequence. We perform rank correlation tests in order to determine the capacity of each observable quantity to probe structural components of stars and infer their evolutionary histories. We also analyze the principal components of classic and asteroseismic observables to highlight the degree of redundancy present in the measured quantities and demonstrate the extent to which information of the model parameters can be extracted. We perform multiple regression using combinations of observable quantities in a grid of evolutionary simulations and appraise the predictive utility of each combination in determining the properties of stars. We identify the combinations that are useful and provide limits to where each type of observable quantity can reveal information about a star. We investigate the accuracy with which targets in the upcoming TESS and PLATO missions can be characterized. We demonstrate that the combination of observations from GAIA and PLATO will allow us to tightly constrain stellar masses, ages, and radii with machine learning for the purposes of Galactic and planetary studies.

Quenching or Bursting: Star Formation Acceleration—A New Methodology for Tracing Galaxy Evolution

NASA Astrophysics Data System (ADS)

Martin, D. Christopher; Gonçalves, Thiago S.; Darvish, Behnam; Seibert, Mark; Schiminovich, David

2017-06-01

We introduce a new methodology for the direct extraction of galaxy physical parameters from multiwavelength photometry and spectroscopy. We use semianalytic models that describe galaxy evolution in the context of large-scale cosmological simulation to provide a catalog of galaxies, star formation histories, and physical parameters. We then apply models of stellar population synthesis and a simple extinction model to calculate the observable broadband fluxes and spectral indices for these galaxies. We use a linear regression analysis to relate physical parameters to observed colors and spectral indices. The result is a set of coefficients that can be used to translate observed colors and indices into stellar mass, star formation rate, and many other parameters, including the instantaneous time derivative of the star formation rate, which we denote the Star Formation Acceleration (SFA), We apply the method to a test sample of galaxies with GALEX photometry and SDSS spectroscopy, deriving relationships between stellar mass, specific star formation rate, and SFA. We find evidence for a mass-dependent SFA in the green valley, with low-mass galaxies showing greater quenching and higher-mass galaxies greater bursting. We also find evidence for an increase in average quenching in galaxies hosting an active galactic nucleus. A simple scenario in which lower-mass galaxies accrete and become satellite galaxies, having their star-forming gas tidally and/or ram-pressure stripped, while higher-mass galaxies receive this gas and react with new star formation, can qualitatively explain our results.

Testing Gene-Gene Interactions in the Case-Parents Design

PubMed Central

Yu, Zhaoxia

2011-01-01

The case-parents design has been widely used to detect genetic associations as it can prevent spurious association that could occur in population-based designs. When examining the effect of an individual genetic locus on a disease, logistic regressions developed by conditioning on parental genotypes provide complete protection from spurious association caused by population stratification. However, when testing gene-gene interactions, it is unknown whether conditional logistic regressions are still robust. Here we evaluate the robustness and efficiency of several gene-gene interaction tests that are derived from conditional logistic regressions. We found that in the presence of SNP genotype correlation due to population stratification or linkage disequilibrium, tests with incorrectly specified main-genetic-effect models can lead to inflated type I error rates. We also found that a test with fully flexible main genetic effects always maintains correct test size and its robustness can be achieved with negligible sacrifice of its power. When testing gene-gene interactions is the focus, the test allowing fully flexible main effects is recommended to be used. PMID:21778736

ON THE THREE-DIMENSIONAL STRUCTURE OF THE MASS, METALLICITY, AND STAR FORMATION RATE SPACE FOR STAR-FORMING GALAXIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lara-Lopez, Maritza A.; Lopez-Sanchez, Angel R.; Hopkins, Andrew M., E-mail: mlopez@aao.gov.au

2013-02-20

We demonstrate that the space formed by the star formation rate (SFR), gas-phase metallicity (Z), and stellar mass (M {sub *}) can be reduced to a plane, as first proposed by Lara-Lopez et al. We study three different approaches to find the best representation of this 3D space, using a principal component analysis (PCA), a regression fit, and binning of the data. The PCA shows that this 3D space can be adequately represented in only two dimensions, i.e., a plane. We find that the plane that minimizes the {chi}{sup 2} for all variables, and hence provides the best representation ofmore » the data, corresponds to a regression fit to the stellar mass as a function of SFR and Z, M {sub *}= f(Z, SFR). We find that the distribution resulting from the median values in bins for our data gives the highest {chi}{sup 2}. We also show that the empirical calibrations to the oxygen abundance used to derive the Fundamental Metallicity Relation have important limitations, which contribute to the apparent inconsistencies. The main problem is that these empirical calibrations do not consider the ionization degree of the gas. Furthermore, the use of the N2 index to estimate oxygen abundances cannot be applied for 12 + log(O/H) {approx}> 8.8 because of the saturation of the [N II] {lambda}6584 line in the high-metallicity regime. Finally, we provide an update of the Fundamental Plane derived by Lara-Lopez et al.« less

Two-trait-locus linkage analysis: A powerful strategy for mapping complex genetic traits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schork, N.J.; Boehnke, M.; Terwilliger, J.D.

1993-11-01

Nearly all diseases mapped to date follow clear Mendelian, single-locus segregation patterns. In contrast, many common familial diseases such as diabetes, psoriasis, several forms of cancer, and schizophrenia are familial and appear to have a genetic component but do not exhibit simple Mendelian transmission. More complex models are required to explain the genetics of these important diseases. In this paper, the authors explore two-trait-locus, two-marker-locus linkage analysis in which two trait loci are mapped simultaneously to separate genetic markers. The authors compare the utility of this approach to standard one-trait-locus, one-marker-locus linkage analysis with and without allowance for heterogeneity. Themore » authors also compare the utility of the two-trait-locus, two-marker-locus analysis to two-trait-locus, one-marker-locus linkage analysis. For common diseases, pedigrees are often bilineal, with disease genes entering via two or more unrelated pedigree members. Since such pedigrees often are avoided in linkage studies, the authors also investigate the relative information content of unilineal and bilineal pedigrees. For the dominant-or-recessive and threshold models that the authors consider, the authors find that two-trait-locus, two-marker-locus linkage analysis can provide substantially more linkage information, as measured by expected maximum lod score, than standard one-trait-locus, one-marker-locus methods, even allowing for heterogeneity, while, for a dominant-or-dominant generating model, one-locus models that allow for heterogeneity extract essentially as much information as the two-trait-locus methods. For these three models, the authors also find that bilineal pedigrees provide sufficient linkage information to warrant their inclusion in such studies. The authors discuss strategies for assessing the significance of the two linkages assumed in two-trait-locus, two-marker-locus models. 37 refs., 1 fig., 4 tabs.« less

17q25 Locus Is Associated With White Matter Hyperintensity Volume in Ischemic Stroke, But Not With Lacunar Stroke Status

PubMed Central

Adib-Samii, Poneh; Rost, Natalia; Traylor, Matthew; Devan, William; Biffi, Alessandro; Lanfranconi, Silvia; Fitzpatrick, Kaitlin; Bevan, Steve; Kanakis, Allison; Valant, Valerie; Gschwendtner, Andreas; Malik, Rainer; Richie, Alexa; Gamble, Dale; Segal, Helen; Parati, Eugenio A.; Ciusani, Emilio; Holliday, Elizabeth G.; Maguire, Jane; Wardlaw, Joanna; Worrall, Bradford; Bis, Joshua; Wiggins, Kerri L.; Longstreth, Will; Kittner, Steve J.; Cheng, Yu-Ching; Mosley, Thomas; Falcone, Guido J.; Furie, Karen L.; Leiva-Salinas, Carlos; Lau, Benison C.; Khan, Muhammed Saleem; Sharma, Pankaj; Fornage, Myriam; Mitchell, Braxton D.; Psaty, Bruce M.; Sudlow, Cathie; Levi, Christopher; Boncoraglio, Giorgio B.; Rothwell, Peter M.; Meschia, James; Dichgans, Martin; Rosand, Jonathan; Markus, Hugh S.

2013-01-01

Background and Purpose Recently, a novel locus at 17q25 was associated with white matter hyperintensities (WMH) on MRI in stroke-free individuals. We aimed to replicate the association with WMH volume (WMHV) in patients with ischemic stroke. If the association acts by promoting a small vessel arteriopathy, it might be expected to also associate with lacunar stroke. Methods We quantified WMH on MRI in the stroke-free hemisphere of 2588 ischemic stroke cases. Association between WMHV and 6 single-nucleotide polymorphisms at chromosome 17q25 was assessed by linear regression. These single-nucleotide polymorphisms were also investigated for association with lacunar stroke in 1854 cases and 51 939 stroke-free controls from METASTROKE. Meta-analyses with previous reports and a genetic risk score approach were applied to identify other novel WMHV risk variants and uncover shared genetic contributions to WMHV in community participants without stroke and ischemic stroke. Results Single-nucleotide polymorphisms at 17q25 were associated with WMHV in ischemic stroke, the most significant being rs9894383 (P=0.0006). In contrast, there was no association between any single-nucleotide polymorphism and lacunar stroke. A genetic risk score analysis revealed further genetic components to WMHV shared between community participants without stroke and ischemic stroke. Conclusions This study provides support for an association between the 17q25 locus and WMH. In contrast, it is not associated with lacunar stroke, suggesting that the association does not act by promoting small-vessel arteriopathy or the same arteriopathy responsible for lacunar infarction. PMID:23674528

Modulation of genetic associations with serum urate levels by body-mass-index in humans.

PubMed

Huffman, Jennifer E; Albrecht, Eva; Teumer, Alexander; Mangino, Massimo; Kapur, Karen; Johnson, Toby; Kutalik, Zoltán; Pirastu, Nicola; Pistis, Giorgio; Lopez, Lorna M; Haller, Toomas; Salo, Perttu; Goel, Anuj; Li, Man; Tanaka, Toshiko; Dehghan, Abbas; Ruggiero, Daniela; Malerba, Giovanni; Smith, Albert V; Nolte, Ilja M; Portas, Laura; Phipps-Green, Amanda; Boteva, Lora; Navarro, Pau; Johansson, Asa; Hicks, Andrew A; Polasek, Ozren; Esko, Tõnu; Peden, John F; Harris, Sarah E; Murgia, Federico; Wild, Sarah H; Tenesa, Albert; Tin, Adrienne; Mihailov, Evelin; Grotevendt, Anne; Gislason, Gauti K; Coresh, Josef; D'Adamo, Pio; Ulivi, Sheila; Vollenweider, Peter; Waeber, Gerard; Campbell, Susan; Kolcic, Ivana; Fisher, Krista; Viigimaa, Margus; Metter, Jeffrey E; Masciullo, Corrado; Trabetti, Elisabetta; Bombieri, Cristina; Sorice, Rossella; Döring, Angela; Reischl, Eva; Strauch, Konstantin; Hofman, Albert; Uitterlinden, Andre G; Waldenberger, Melanie; Wichmann, H-Erich; Davies, Gail; Gow, Alan J; Dalbeth, Nicola; Stamp, Lisa; Smit, Johannes H; Kirin, Mirna; Nagaraja, Ramaiah; Nauck, Matthias; Schurmann, Claudia; Budde, Kathrin; Farrington, Susan M; Theodoratou, Evropi; Jula, Antti; Salomaa, Veikko; Sala, Cinzia; Hengstenberg, Christian; Burnier, Michel; Mägi, Reedik; Klopp, Norman; Kloiber, Stefan; Schipf, Sabine; Ripatti, Samuli; Cabras, Stefano; Soranzo, Nicole; Homuth, Georg; Nutile, Teresa; Munroe, Patricia B; Hastie, Nicholas; Campbell, Harry; Rudan, Igor; Cabrera, Claudia; Haley, Chris; Franco, Oscar H; Merriman, Tony R; Gudnason, Vilmundur; Pirastu, Mario; Penninx, Brenda W; Snieder, Harold; Metspalu, Andres; Ciullo, Marina; Pramstaller, Peter P; van Duijn, Cornelia M; Ferrucci, Luigi; Gambaro, Giovanni; Deary, Ian J; Dunlop, Malcolm G; Wilson, James F; Gasparini, Paolo; Gyllensten, Ulf; Spector, Tim D; Wright, Alan F; Hayward, Caroline; Watkins, Hugh; Perola, Markus; Bochud, Murielle; Kao, W H Linda; Caulfield, Mark; Toniolo, Daniela; Völzke, Henry; Gieger, Christian; Köttgen, Anna; Vitart, Veronique

2015-01-01

We tested for interactions between body mass index (BMI) and common genetic variants affecting serum urate levels, genome-wide, in up to 42569 participants. Both stratified genome-wide association (GWAS) analyses, in lean, overweight and obese individuals, and regression-type analyses in a non BMI-stratified overall sample were performed. The former did not uncover any novel locus with a major main effect, but supported modulation of effects for some known and potentially new urate loci. The latter highlighted a SNP at RBFOX3 reaching genome-wide significant level (effect size 0.014, 95% CI 0.008-0.02, Pinter= 2.6 x 10-8). Two top loci in interaction term analyses, RBFOX3 and ERO1LB-EDARADD, also displayed suggestive differences in main effect size between the lean and obese strata. All top ranking loci for urate effect differences between BMI categories were novel and most had small magnitude but opposite direction effects between strata. They include the locus RBMS1-TANK (men, Pdifflean-overweight= 4.7 x 10-8), a region that has been associated with several obesity related traits, and TSPYL5 (men, Pdifflean-overweight= 9.1 x 10-8), regulating adipocytes-produced estradiol. The top-ranking known urate loci was ABCG2, the strongest known gout risk locus, with an effect halved in obese compared to lean men (Pdifflean-obese= 2 x 10-4). Finally, pathway analysis suggested a role for N-glycan biosynthesis as a prominent urate-associated pathway in the lean stratum. These results illustrate a potentially powerful way to monitor changes occurring in obesogenic environment.

Characteristics of acupuncture users among internal medicine patients in Germany.

PubMed

Cramer, Holger; Chung, Vincent C H; Lauche, Romy; Zhang, Yan; Zhang, Anthony; Langhorst, Jost; Dobos, Gustav

2015-06-01

To identify socio-demographic and health-related factors associated with (a) acupuncture use and (b) the rated helpfulness of acupuncture among internal medicine patients. Data from a larger cross-sectional trial were reanalyzed. Patients who had used acupuncture for managing their primary medical complaint were compared to patients who had not. Predictors for (a) acupuncture use and (b) rated helpfulness were determined using logistic regression analyses. Of 2486 included patients, 51.49% reported acupuncture use and 39.22% reported no prior use. The use of acupuncture was associated with higher age, i.e. those aged 50-64 were more likely to have used acupuncture, while those younger than 30 were less likely. Patients with spinal pain, fibromyalgia, or headache were more likely to be acupuncture users; while IBS patients were less likely. Patients with good to excellent health status, high external-social health locus of control and current smokers were less likely to have used acupuncture. Among those who had used acupuncture, 42.34% perceived the treatment as helpful, while 35.94% did not. Rated helpfulness was associated with female gender, full-time employment, high health satisfaction, and high internal health locus of control. Those with a diagnosis of osteoarthritis or inflammatory bowel disease were more likely to find acupuncture helpful; those with headache or other types of chronic pain were less likely to find acupuncture helpful. Acupuncture was used by more than half of internal medicine patients. Prevalence and rated helpfulness of acupuncture use was associated with the patients' medical condition, sociodemography, and health locus of control. Copyright © 2015 Elsevier Ltd. All rights reserved.

Modulation of Genetic Associations with Serum Urate Levels by Body-Mass-Index in Humans

PubMed Central

Huffman, Jennifer E.; Albrecht, Eva; Teumer, Alexander; Mangino, Massimo; Kapur, Karen; Johnson, Toby; Kutalik, Zoltán; Pirastu, Nicola; Pistis, Giorgio; Lopez, Lorna M.; Haller, Toomas; Salo, Perttu; Goel, Anuj; Li, Man; Tanaka, Toshiko; Dehghan, Abbas; Ruggiero, Daniela; Malerba, Giovanni; Smith, Albert V.; Nolte, Ilja M.; Portas, Laura; Phipps-Green, Amanda; Boteva, Lora; Navarro, Pau; Johansson, Asa; Hicks, Andrew A.; Polasek, Ozren; Esko, Tõnu; Peden, John F.; Harris, Sarah E.; Murgia, Federico; Wild, Sarah H.; Tenesa, Albert; Tin, Adrienne; Mihailov, Evelin; Grotevendt, Anne; Gislason, Gauti K.; Coresh, Josef; D'Adamo, Pio; Ulivi, Sheila; Vollenweider, Peter; Waeber, Gerard; Campbell, Susan; Kolcic, Ivana; Fisher, Krista; Viigimaa, Margus; Metter, Jeffrey E.; Masciullo, Corrado; Trabetti, Elisabetta; Bombieri, Cristina; Sorice, Rossella; Döring, Angela; Reischl, Eva; Strauch, Konstantin; Hofman, Albert; Uitterlinden, Andre G.; Waldenberger, Melanie; Wichmann, H-Erich; Davies, Gail; Gow, Alan J.; Dalbeth, Nicola; Stamp, Lisa; Smit, Johannes H.; Kirin, Mirna; Nagaraja, Ramaiah; Nauck, Matthias; Schurmann, Claudia; Budde, Kathrin; Farrington, Susan M.; Theodoratou, Evropi; Jula, Antti; Salomaa, Veikko; Sala, Cinzia; Hengstenberg, Christian; Burnier, Michel; Mägi, Reedik; Klopp, Norman; Kloiber, Stefan; Schipf, Sabine; Ripatti, Samuli; Cabras, Stefano; Soranzo, Nicole; Homuth, Georg; Nutile, Teresa; Munroe, Patricia B.; Hastie, Nicholas; Campbell, Harry; Rudan, Igor; Cabrera, Claudia; Haley, Chris; Franco, Oscar H.; Merriman, Tony R.; Gudnason, Vilmundur; Pirastu, Mario; Penninx, Brenda W.; Snieder, Harold; Metspalu, Andres; Ciullo, Marina; Pramstaller, Peter P.; van Duijn, Cornelia M.; Ferrucci, Luigi; Gambaro, Giovanni; Deary, Ian J.; Dunlop, Malcolm G.; Wilson, James F.; Gasparini, Paolo; Gyllensten, Ulf; Spector, Tim D.; Wright, Alan F.; Hayward, Caroline; Watkins, Hugh; Perola, Markus; Bochud, Murielle; Kao, W. H. Linda; Caulfield, Mark; Toniolo, Daniela; Völzke, Henry; Gieger, Christian; Köttgen, Anna; Vitart, Veronique

2015-01-01

We tested for interactions between body mass index (BMI) and common genetic variants affecting serum urate levels, genome-wide, in up to 42569 participants. Both stratified genome-wide association (GWAS) analyses, in lean, overweight and obese individuals, and regression-type analyses in a non BMI-stratified overall sample were performed. The former did not uncover any novel locus with a major main effect, but supported modulation of effects for some known and potentially new urate loci. The latter highlighted a SNP at RBFOX3 reaching genome-wide significant level (effect size 0.014, 95% CI 0.008-0.02, Pinter= 2.6 x 10-8). Two top loci in interaction term analyses, RBFOX3 and ERO1LB-EDARADD, also displayed suggestive differences in main effect size between the lean and obese strata. All top ranking loci for urate effect differences between BMI categories were novel and most had small magnitude but opposite direction effects between strata. They include the locus RBMS1-TANK (men, Pdifflean-overweight= 4.7 x 10-8), a region that has been associated with several obesity related traits, and TSPYL5 (men, Pdifflean-overweight= 9.1 x 10-8), regulating adipocytes-produced estradiol. The top-ranking known urate loci was ABCG2, the strongest known gout risk locus, with an effect halved in obese compared to lean men (Pdifflean-obese= 2 x 10-4). Finally, pathway analysis suggested a role for N-glycan biosynthesis as a prominent urate-associated pathway in the lean stratum. These results illustrate a potentially powerful way to monitor changes occurring in obesogenic environment. PMID:25811787

Psychological predictors for health-related quality of life and disability in persons with chronic obstructive pulmonary disease (COPD).

PubMed

Mewes, Ricarda; Rief, Winfried; Kenn, Klaus; Ried, Jens; Stenzel, Nikola

2016-01-01

Individuals with chronic obstructive pulmonary disease (COPD) exhibit low physical and mental health-related quality of life (HRQL) and high susceptibility to disability. We investigated the influence of psychological factors on HRQL and disability in COPD individuals recruited from the general population. In line with Leventhal's common sense model, we expected psychological factors to be associated with HRQL and disability even after controlling for medical status. Individuals with COPD (n = 502; 59.7 years old; GOLD grades were I: 3%, II: 17%, III: 34%, IV: 46%) were assessed through an online survey administered via COPD patient organisations in Germany. Individuals filled in the Short Form Health Survey (SF-12), COPD Assessment Test, Patient Health Questionnaire (modules: GAD-2, PHQ-15, PHQ-9), Brief Illness Perception Questionnaire, a questionnaire that assesses causal illness attributions, and the internal illness-related locus of control scale of the 'KKG questionnaire for the assessment of control beliefs about illness and health'. Multiple linear regressions were calculated. The investigated factors explained high variances (disability = 56%, physical HRQL = 28%, mental HRQL = 63%, p ≤ .001). Better mental health, more optimistic illness perceptions, attribution to psychological causes, and stronger internal locus of control were associated with lower disability and better HRQL. Comorbid somatic symptoms contributed to high disability and low quality of life. Psychological factors, such as illness perception, attribution and internal locus of control, were associated with disability and HRQL. These factors should be considered when designing treatments for individuals with COPD, and adequate interventions should be provided to enhance illness understanding and self-management skills.

High-resolution mapping of the x-linked hypohidrotic ectodermal dysplasia (EDA) locus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zonana, J.; Jones, M.; Litt, M.

1992-11-01

The X-linked hypohidrotic ectodermal dysplasia (EDA) locus has been previously localized to the subchromosomal region Xq11-q21.1. The authors have extended previous linkage studies and analyzed linkage between the EDA locus and 10 marker loci, including five new loci, in 41 families. Four of the marker loci showed no recombination with the EDA locus, and six other loci were also linked to the EDA locus with recombination fractions of .009-.075. Multipoint analysis gave support to the placement of the PGK1P1 locus proximal to the EDA locus and the DXS453 and PGK1 loci distal to EDA. Further ordering of the loci couldmore » be inferred from a human-rodent somatic cell hybrid derived from an affected female with EDA and an X;9 translocation and from studies of an affected male with EDA and a submicroscopic deletion. Three of the proximal marker loci, which showed no recombination with the EDA locus, when used in combination, were informative in 92% of females. The closely linked flanking polymorphic loci DXS339 and DXS453 had heterozygosites of 72% and 76%, respectively, and when used jointly, they were doubly informative in 52% of females. The human DXS732 locus was defined by a conserved mouse probe pcos169E/4 (DXCrc169 locus) that consegregates with the mouse tabby (Ta) locus, a potential homologue to the EDA locus. The absence of recombination between EDA and the DXSA732 locus lends support to the hypothesis that the DXCrc169 locus in the mouse and the DXS732 locus in humans may contain candidate sequences for the Ta and EDA genes, respectively. 36 refs., 1 fig., 5 tabs.« less

Disruption of MBD5 contributes to a spectrum of psychopathology and neurodevelopmental abnormalities

PubMed Central

Hodge, Jennelle C.; Mitchell, Elyse; Pillalamarri, Vamsee; Toler, Tomi L.; Bartel, Frank; Kearney, Hutton M.; Zou, Ying S.; Tan, Wen-Hann; Hanscom, Carrie; Kirmani, Salman; Hanson, Rae R.; Skinner, Steven A.; Rogers, Curtis; Everman, David B.; Boyd, Ellen; Mullegama, Sureni V.; Keelean-Fuller, Debra; Powell, Cynthia M.; Elsea, Sarah H.; Morton, Cynthia C.; Gusella, James F.; DuPont, Barbara; Chaubey, Alka; Lin, Angela E.; Talkowski, Michael E.

2016-01-01

Microdeletions of chromosomal region 2q23.1 that disrupt MBD5 contribute to a spectrum of neurodevelopmental phenotypes, however the impact of this locus in human psychopathology has not been described. To characterize the structural variation landscape of MBD5 disruptions and the associated psychopathology, 22 individuals with genomic disruption of MBD5 (translocation, point mutation, and deletion) were identified through whole-genome sequencing or cytogenomic microarray at 11 molecular diagnostic centers. The genomic impact ranged from a single base pair to 5.4 Mb. Parents were available for 11 cases, all of which confirmed the rearrangement arose de novo. Phenotypes were largely indistinguishable between patients with full-segment 2q23.1 deletions and those with intragenic MBD5 rearrangements, including alterations confined entirely to the 5′UTR, confirming the critical impact of non-coding sequence at this locus. We found heterogeneous, multi-system pathogenic effects of MBD5 disruption and characterized the associated spectrum of psychopathology, which includes sensory integration disorder, anxiety, self-hugging, bipolar disorder and others. Importantly, unique features of the oldest assessed patient were early-onset dementia and behavioral regression. Analyses also revealed phenotypes that distinguish MBD5 disruptions from seven well-established syndromes with significant diagnostic overlap. This study indicates that haploinsufficiency of MBD5 causes diverse phenotypes, yields insight into the spectrum of resulting neurodevelopmental and behavioral psychopathology, and provides clinical context for interpretation of MBD5 structural variations. Empirical evidence also suggests that disruption of non-coding MBD5 regulatory regions is sufficient for clinical manifestation, highlighting the limitations of exon-focused assessments. These results suggest an ongoing perturbation of neurological function throughout the lifespan, including risks for neurobehavioral regression and early-onset dementia. PMID:23587880

Segregation of a QTL cluster for home-cage activity using a new mapping method based on regression analysis of congenic mouse strains

PubMed Central

Kato, S; Ishii, A; Nishi, A; Kuriki, S; Koide, T

2014-01-01

Recent genetic studies have shown that genetic loci with significant effects in whole-genome quantitative trait loci (QTL) analyses were lost or weakened in congenic strains. Characterisation of the genetic basis of this attenuated QTL effect is important to our understanding of the genetic mechanisms of complex traits. We previously found that a consomic strain, B6-Chr6CMSM, which carries chromosome 6 of a wild-derived strain MSM/Ms on the genetic background of C57BL/6J, exhibited lower home-cage activity than C57BL/6J. In the present study, we conducted a composite interval QTL analysis using the F2 mice derived from a cross between C57BL/6J and B6-Chr6CMSM. We found one QTL peak that spans 17.6 Mbp of chromosome 6. A subconsomic strain that covers the entire QTL region also showed lower home-cage activity at the same level as the consomic strain. We developed 15 congenic strains, each of which carries a shorter MSM/Ms-derived chromosomal segment from the subconsomic strain. Given that the results of home-cage activity tests on the congenic strains cannot be explained by a simple single-gene model, we applied regression analysis to segregate the multiple genetic loci. The results revealed three loci (loci 1–3) that have the effect of reducing home-cage activity and one locus (locus 4) that increases activity. We also found that the combination of loci 3 and 4 cancels out the effects of the congenic strains, which indicates the existence of a genetic mechanism related to the loss of QTLs. PMID:24781804

AMP kinase-related kinase NUAK2 affects tumor growth, migration, and clinical outcome of human melanoma.

PubMed

Namiki, Takeshi; Tanemura, Atsushi; Valencia, Julio C; Coelho, Sergio G; Passeron, Thierry; Kawaguchi, Masakazu; Vieira, Wilfred D; Ishikawa, Masashi; Nishijima, Wataru; Izumo, Toshiyuki; Kaneko, Yasuhiko; Katayama, Ichiro; Yamaguchi, Yuji; Yin, Lanlan; Polley, Eric C; Liu, Hongfang; Kawakami, Yutaka; Eishi, Yoshinobu; Takahashi, Eishi; Yokozeki, Hiroo; Hearing, Vincent J

2011-04-19

The identification of genes that participate in melanomagenesis should suggest strategies for developing therapeutic modalities. We used a public array comparative genomic hybridization (CGH) database and real-time quantitative PCR (qPCR) analyses to identify the AMP kinase (AMPK)-related kinase NUAK2 as a candidate gene for melanomagenesis, and we analyzed its functions in melanoma cells. Our analyses had identified a locus at 1q32 where genomic gain is strongly associated with tumor thickness, and we used real-time qPCR analyses and regression analyses to identify NUAK2 as a candidate gene at that locus. Associations of relapse-free survival and overall survival of 92 primary melanoma patients with NUAK2 expression measured using immunohistochemistry were investigated using Kaplan-Meier curves, log rank tests, and Cox regression models. Knockdown of NUAK2 induces senescence and reduces S-phase, decreases migration, and down-regulates expression of mammalian target of rapamycin (mTOR). In vivo analysis demonstrated that knockdown of NUAK2 suppresses melanoma tumor growth in mice. Survival analysis showed that the risk of relapse is greater in acral melanoma patients with high levels of NUAK2 expression than in acral melanoma patients with low levels of NUAK2 expression (hazard ratio = 3.88; 95% confidence interval = 1.44-10.50; P = 0.0075). These data demonstrate that NUAK2 expression is significantly associated with the oncogenic features of melanoma cells and with the survival of acral melanoma patients. NUAK2 may provide a drug target to suppress melanoma progression. This study further supports the importance of NUAK2 in cancer development and tumor progression, while AMPK has antioncogenic properties.

Identification of rs7350481 at chromosome 11q23.3 as a novel susceptibility locus for metabolic syndrome in Japanese individuals by an exome-wide association study.

PubMed

Yamada, Yoshiji; Sakuma, Jun; Takeuchi, Ichiro; Yasukochi, Yoshiki; Kato, Kimihiko; Oguri, Mitsutoshi; Fujimaki, Tetsuo; Horibe, Hideki; Muramatsu, Masaaki; Sawabe, Motoji; Fujiwara, Yoshinori; Taniguchi, Yu; Obuchi, Shuichi; Kawai, Hisashi; Shinkai, Shoji; Mori, Seijiro; Arai, Tomio; Tanaka, Masashi

2017-06-13

We have performed exome-wide association studies to identify genetic variants that influence body mass index or confer susceptibility to obesity or metabolic syndrome in Japanese. The exome-wide association study for body mass index included 12,890 subjects, and those for obesity and metabolic syndrome included 12,968 subjects (3954 individuals with obesity, 9014 controls) and 6817 subjects (3998 individuals with MetS, 2819 controls), respectively. Exome-wide association studies were performed with Illumina HumanExome-12 DNA Analysis BeadChip or Infinium Exome-24 BeadChip arrays. The relation of genotypes of single nucleotide polymorphisms to body mass index was examined by linear regression analysis, and that of allele frequencies of single nucleotide polymorphisms to obesity or metabolic syndrome was evaluated with Fisher's exact test. The exome-wide association studies identified six, 11, and 40 single nucleotide polymorphisms as being significantly associated with body mass index, obesity (P <1.21 × 10-6), or metabolic syndrome (P <1.20 × 10-6), respectively. Subsequent multivariable logistic regression analysis with adjustment for age and sex revealed that three and five single nucleotide polymorphisms were related (P < 0.05) to obesity or metabolic syndrome, respectively, with one of these latter polymorphisms-rs7350481 (C/T) at chromosome 11q23.3-also being significantly (P < 3.13 × 10-4) associated with metabolic syndrome. The polymorphism rs7350481 may thus be a novel susceptibility locus for metabolic syndrome in Japanese. In addition, single nucleotide polymorphisms in three genes (CROT, TSC1, RIN3) and at four loci (ANKK1, ZNF804B, CSRNP3, 17p11.2) were implicated as candidate determinants of obesity and metabolic syndrome, respectively.

African Ancestry Analysis and Admixture Genetic Mapping for Proliferative Diabetic Retinopathy in African Americans

PubMed Central

Tandon, Arti; Chen, Ching J.; Penman, Alan; Hancock, Heather; James, Maurice; Husain, Deeba; Andreoli, Christopher; Li, Xiaohui; Kuo, Jane Z.; Idowu, Omolola; Riche, Daniel; Papavasilieou, Evangelia; Brauner, Stacey; Smith, Sataria O.; Hoadley, Suzanne; Richardson, Cole; Kieser, Troy; Vazquez, Vanessa; Chi, Cheryl; Fernandez, Marlene; Harden, Maegan; Cotch, Mary Frances; Siscovick, David; Taylor, Herman A.; Wilson, James G.; Reich, David; Wong, Tien Y.; Klein, Ronald; Klein, Barbara E. K.; Rotter, Jerome I.; Patterson, Nick; Sobrin, Lucia

2015-01-01

Purpose. To examine the relationship between proportion of African ancestry (PAA) and proliferative diabetic retinopathy (PDR) and to identify genetic loci associated with PDR using admixture mapping in African Americans with type 2 diabetes (T2D). Methods. Between 1993 and 2013, 1440 participants enrolled in four different studies had fundus photographs graded using the Early Treatment Diabetic Retinopathy Study scale. Cases (n = 305) had PDR while controls (n = 1135) had nonproliferative diabetic retinopathy (DR) or no DR. Covariates included diabetes duration, hemoglobin A1C, systolic blood pressure, income, and education. Genotyping was performed on the Affymetrix platform. The association between PAA and PDR was evaluated using logistic regression. Genome-wide admixture scanning was performed using ANCESTRYMAP software. Results. In the univariate analysis, PDR was associated with increased PAA (odds ratio [OR] = 1.36, 95% confidence interval [CI] = 1.16–1.59, P = 0.0002). In multivariate regression adjusting for traditional DR risk factors, income and education, the association between PAA and PDR was attenuated and no longer significant (OR = 1.21, 95% CI = 0.59–2.47, P = 0.61). For the admixture analyses, the maximum genome-wide score was 1.44 on chromosome 1. Conclusions. In this largest study of PDR in African Americans with T2D to date, an association between PAA and PDR is not present after adjustment for clinical, demographic, and socioeconomic factors. No genome-wide significant locus (defined as having a locus-genome statistic > 5) was identified with admixture analysis. Further analyses with even larger sample sizes are needed to definitively assess if any admixture signal for DR is present. PMID:26098467

On the Statistical Properties of the Lower Main Sequence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Angelou, George C.; Bellinger, Earl P.; Hekker, Saskia

Astronomy is in an era where all-sky surveys are mapping the Galaxy. The plethora of photometric, spectroscopic, asteroseismic, and astrometric data allows us to characterize the comprising stars in detail. Here we quantify to what extent precise stellar observations reveal information about the properties of a star, including properties that are unobserved, or even unobservable. We analyze the diagnostic potential of classical and asteroseismic observations for inferring stellar parameters such as age, mass, and radius from evolutionary tracks of solar-like oscillators on the lower main sequence. We perform rank correlation tests in order to determine the capacity of each observablemore » quantity to probe structural components of stars and infer their evolutionary histories. We also analyze the principal components of classic and asteroseismic observables to highlight the degree of redundancy present in the measured quantities and demonstrate the extent to which information of the model parameters can be extracted. We perform multiple regression using combinations of observable quantities in a grid of evolutionary simulations and appraise the predictive utility of each combination in determining the properties of stars. We identify the combinations that are useful and provide limits to where each type of observable quantity can reveal information about a star. We investigate the accuracy with which targets in the upcoming TESS and PLATO missions can be characterized. We demonstrate that the combination of observations from GAIA and PLATO will allow us to tightly constrain stellar masses, ages, and radii with machine learning for the purposes of Galactic and planetary studies.« less

Stellar Absorption Line Analysis of Local Star-forming Galaxies: The Relation between Stellar Mass, Metallicity, Dust Attenuation, and Star Formation Rate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jabran Zahid, H.; Kudritzki, Rolf-Peter; Ho, I-Ting

We analyze the optical continuum of star-forming galaxies in the Sloan Digital Sky Survey by fitting stacked spectra with stellar population synthesis models to investigate the relation between stellar mass, stellar metallicity, dust attenuation, and star formation rate. We fit models calculated with star formation and chemical evolution histories that are derived empirically from multi-epoch observations of the stellar mass–star formation rate and the stellar mass–gas-phase metallicity relations, respectively. We also fit linear combinations of single-burst models with a range of metallicities and ages. Star formation and chemical evolution histories are unconstrained for these models. The stellar mass–stellar metallicity relationsmore » obtained from the two methods agree with the relation measured from individual supergiant stars in nearby galaxies. These relations are also consistent with the relation obtained from emission-line analysis of gas-phase metallicity after accounting for systematic offsets in the gas-phase metallicity. We measure dust attenuation of the stellar continuum and show that its dependence on stellar mass and star formation rate is consistent with previously reported results derived from nebular emission lines. However, stellar continuum attenuation is smaller than nebular emission line attenuation. The continuum-to-nebular attenuation ratio depends on stellar mass and is smaller in more massive galaxies. Our consistent analysis of stellar continuum and nebular emission lines paves the way for a comprehensive investigation of stellar metallicities of star-forming and quiescent galaxies.« less

Predictors of Medical or Surgical and Psychiatric Hospitalizations Among a Population-Based Cohort of Homeless Adults

PubMed Central

Chambers, Catharine; Katic, Marko; Chiu, Shirley; Redelmeier, Donald A.; Levinson, Wendy; Kiss, Alex

2013-01-01

Objectives. We identified factors associated with inpatient hospitalizations among a population-based cohort of homeless adults in Toronto, Ontario. Methods. We recruited participants from shelters and meal programs. We then linked them to administrative databases to capture hospital admissions during the study (2005–2009). We used logistic regression to identify predictors of medical or surgical and psychiatric hospitalizations. Results. Among 1165 homeless adults, 20% had a medical or surgical hospitalization, and 12% had a psychiatric hospitalization during the study. These individuals had a total of 921 hospitalizations, of which 548 were medical or surgical and 373 were psychiatric. Independent predictors of medical or surgical hospitalization included birth in Canada, having a primary care provider, higher perceived external health locus of control, and lower health status. Independent predictors of psychiatric hospitalization included being a current smoker, having a recent mental health problem, and having a lower perceived internal health locus of control. Being accompanied by a partner or dependent children was protective for hospitalization. Conclusions. Health care need was a strong predictor of medical or surgical and psychiatric hospitalizations. Some hospitalizations among homeless adults were potentially avoidable, whereas others represented an unavoidable use of health services. PMID:24148040

Perceptions of control in adults with epilepsy.

PubMed

Gehlert, S

1994-01-01

That psychosocial problems are extant in epilepsy is evidenced by a suicide rate among epileptic persons five times that of the general population and an unemployment rate estimated to be more than twice that of the population as a whole. External perceptions of control secondary to repeated episodes of seizure activity that generalize to the social sphere have been implicated as causes of these problems. The hypothesis that individuals who continue to have seizures become more and more external in perceptions of control was tested by a survey mailed to a sample of individuals with epilepsy in a metropolitan area of the Midwest. Dependent variables were, scores on instruments measuring locus of control and attributional style. The independent variable was a measure of seizure control based on present age, age at onset, and length of time since last seizure. Gender, socioeconomic status, and certain parenting characteristics were included as control variables, as they are also known to affect perceptions of control. Analysis by multiple regression techniques supported the study's hypothesis when perceptions of control was conceptualized as learned helplessness for bad, but not for good, events. The hypothesis was not confirmed when perceptions of control was conceptualized as either general or health locus of control.

Chemogenetic locus coeruleus activation restores reversal learning in a rat model of Alzheimer's disease.

PubMed

Rorabaugh, Jacki M; Chalermpalanupap, Termpanit; Botz-Zapp, Christian A; Fu, Vanessa M; Lembeck, Natalie A; Cohen, Robert M; Weinshenker, David

2017-11-01

See Grinberg and Heinsen (doi:10.1093/brain/awx261) for a scientific commentary on this article. Clinical evidence suggests that aberrant tau accumulation in the locus coeruleus and noradrenergic dysfunction may be a critical early step in Alzheimer’s disease progression. Yet, an accurate preclinical model of these phenotypes that includes early pretangle tau accrual in the locus coeruleus, loss of locus coeruleus innervation and deficits locus coeruleus/norepinephrine modulated behaviours, does not exist, hampering the identification of underlying mechanisms and the development of locus coeruleus-based therapies. Here, a transgenic rat (TgF344-AD) expressing disease-causing mutant amyloid precursor protein (APPsw) and presenilin-1 (PS1ΔE9) was characterized for histological and behavioural signs of locus coeruleus dysfunction reminiscent of mild cognitive impairment/early Alzheimer’s disease. In TgF344-AD rats, hyperphosphorylated tau was detected in the locus coeruleus prior to accrual in the medial entorhinal cortex or hippocampus, and tau pathology in the locus coeruleus was negatively correlated with noradrenergic innervation in the medial entorhinal cortex. Likewise, TgF344-AD rats displayed progressive loss of hippocampal norepinephrine levels and locus coeruleus fibres in the medial entorhinal cortex and dentate gyrus, with no frank noradrenergic cell body loss. Cultured mouse locus coeruleus neurons expressing hyperphosphorylation-prone mutant human tau had shorter neurites than control neurons, but similar cell viability, suggesting a causal link between pretangle tau accrual and altered locus coeruleus fibre morphology. TgF344-AD rats had impaired reversal learning in the Morris water maze compared to their wild-type littermates, which was rescued by chemogenetic locus coeruleus activation via designer receptors exclusively activated by designer drugs (DREADDs). Our results indicate that TgF344-AD rats uniquely meet several key criteria for a suitable model of locus coeruleus pathology and dysfunction early in Alzheimer’s disease progression, and suggest that a substantial window of opportunity for locus coeruleus/ norepinephrine-based therapeutics exists.

STELLAR ATMOSPHERES, ATMOSPHERIC EXTENSION, AND FUNDAMENTAL PARAMETERS: WEIGHING STARS USING THE STELLAR MASS INDEX

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neilson, Hilding R.; Lester, John B.; Baron, Fabien

2016-10-20

One of the great challenges of understanding stars is measuring their masses. The best methods for measuring stellar masses include binary interaction, asteroseismology, and stellar evolution models, but these methods are not ideal for red giant and supergiant stars. In this work, we propose a novel method for inferring stellar masses of evolved red giant and supergiant stars using interferometric and spectrophotometric observations combined with spherical model stellar atmospheres to measure what we call the stellar mass index, defined as the ratio between the stellar radius and mass. The method is based on the correlation between different measurements of angularmore » diameter, used as a proxy for atmospheric extension, and fundamental stellar parameters. For a given star, spectrophotometry measures the Rosseland angular diameter while interferometric observations generally probe a larger limb-darkened angular diameter. The ratio of these two angular diameters is proportional to the relative extension of the stellar atmosphere, which is strongly correlated to the star’s effective temperature, radius, and mass. We show that these correlations are strong and can lead to precise measurements of stellar masses.« less

Characteristics of patients with internal diseases who use relaxation techniques as a coping strategy.

PubMed

Cramer, Holger; Lauche, Romy; Langhorst, Jost; Dobos, Gustav; Paul, Anna

2013-10-01

To assess sociodemographic, clinical, and psychological characteristics of patients with internal diseases who use relaxation techniques as a coping strategy. Cross-sectional analysis among patients with internal diseases. Department of Internal and Integrative Medicine at an academic teaching hospital in Germany. Prior use of relaxation techniques (e.g. meditation, autogenic training), perceived benefit, and perceived harm. Potential predictors of relaxation techniques use (sociodemographic characteristics, health behavior, internal medicine diagnosis, general health status, mental health, satisfaction, and health locus of control) were tested using multiple logistic regression analysis. Of 2486 participants, 1075 (43.2%) reported to have used relaxation techniques, 648 (60.3%) reported benefits, and 11 (1.0%) reported harms. Use of relaxation techniques was independently associated with female gender (Odds ratio [OR]=1.43; 95% confidence interval [CI]=1.08-1.89), higher education (OR=1.32; 95%CI=1.03-1.71), fibromyalgia (OR=1.78; 95%CI=1.22-2.61), and internal health locus of control (OR=1.27; 95%CI=1.01-1.60). Use of relaxation techniques was negatively associated with age below 30 (OR=0.32; 95%CI=0.20-0.52) or above 64 (OR=0.65; 95%CI=0.49-0.88), full-time employment (OR=0.75; 95%CI=0.57-0.98), current smoking (OR=0.72; 95%CI=0.54-0.95), osteoarthritis (OR=0.51; 95%CI=0.34-0.77), rheumatic arthritis (OR=0.59; 95%CI=0.37-0.93), good to excellent health status (OR=0.70; 95%CI=0.52-0.96), and high life satisfaction (OR=0.78; 95%CI=0.62-0.98). In a German sample of patients with internal diseases, relaxation techniques were used as a coping strategy by about 43%. Users were more likely to be middle-aged, female, well-educated, diagnosed with fibromyalgia, not smoking, not full-time employed, and not to have a good health status or high life satisfaction. A high internal health locus of control predicted relaxation techniques use. Considering health locus of control might improve adherence to relaxation techniques in internal medicine patients. Copyright © 2013 Elsevier Ltd. All rights reserved.

Improving power and robustness for detecting genetic association with extreme-value sampling design.

PubMed

Chen, Hua Yun; Li, Mingyao

2011-12-01

Extreme-value sampling design that samples subjects with extremely large or small quantitative trait values is commonly used in genetic association studies. Samples in such designs are often treated as "cases" and "controls" and analyzed using logistic regression. Such a case-control analysis ignores the potential dose-response relationship between the quantitative trait and the underlying trait locus and thus may lead to loss of power in detecting genetic association. An alternative approach to analyzing such data is to model the dose-response relationship by a linear regression model. However, parameter estimation from this model can be biased, which may lead to inflated type I errors. We propose a robust and efficient approach that takes into consideration of both the biased sampling design and the potential dose-response relationship. Extensive simulations demonstrate that the proposed method is more powerful than the traditional logistic regression analysis and is more robust than the linear regression analysis. We applied our method to the analysis of a candidate gene association study on high-density lipoprotein cholesterol (HDL-C) which includes study subjects with extremely high or low HDL-C levels. Using our method, we identified several SNPs showing a stronger evidence of association with HDL-C than the traditional case-control logistic regression analysis. Our results suggest that it is important to appropriately model the quantitative traits and to adjust for the biased sampling when dose-response relationship exists in extreme-value sampling designs. © 2011 Wiley Periodicals, Inc.

Gene-environment interaction study for BMI reveals interactions between genetic factors and physical activity, alcohol consumption and socioeconomic status

PubMed Central

Karlsson, Torgny; Ek, Weronica E.

2017-01-01

Previous genome-wide association studies (GWAS) have identified hundreds of genetic loci to be associated with body mass index (BMI) and risk of obesity. Genetic effects can differ between individuals depending on lifestyle or environmental factors due to gene-environment interactions. In this study, we examine gene-environment interactions in 362,496 unrelated participants with Caucasian ancestry from the UK Biobank resource. A total of 94 BMI-associated SNPs, selected from a previous GWAS on BMI, were used to construct weighted genetic scores for BMI (GSBMI). Linear regression modeling was used to estimate the effect of gene-environment interactions on BMI for 131 lifestyle factors related to: dietary habits, smoking and alcohol consumption, physical activity, socioeconomic status, mental health, sleeping patterns, as well as female-specific factors such as menopause and childbirth. In total, 15 lifestyle factors were observed to interact with GSBMI, of which alcohol intake frequency, usual walking pace, and Townsend deprivation index, a measure of socioeconomic status, were all highly significant (p = 1.45*10−29, p = 3.83*10−26, p = 4.66*10−11, respectively). Interestingly, the frequency of alcohol consumption, rather than the total weekly amount resulted in a significant interaction. The FTO locus was the strongest single locus interacting with any of the lifestyle factors. However, 13 significant interactions were also observed after omitting the FTO locus from the genetic score. Our analyses indicate that many lifestyle factors modify the genetic effects on BMI with some groups of individuals having more than double the effect of the genetic score. However, the underlying causal mechanisms of gene-environmental interactions are difficult to deduce from cross-sectional data alone and controlled experiments are required to fully characterise the causal factors. PMID:28873402

Affective personality as cognitive-emotional presymptom profiles regulatory for self-reported health predispositions.

PubMed

Archer, T; Adolfsson, B; Karlsson, E

2008-08-01

Three studies that examined the links between affective personality, as constructed from responses to the Positive Affect (PA) and Negative Affect (NA) Scale (PANAS), and individuals' self-report of self-esteem, intrinsic motivation and Beck's Depression Inventory (BDI) depression in high school students and persons in working occupations are described. Self-report estimations of several other neuropsychiatric and psychosocial variables including, the Uppsala Sleep Inventory (USI), the Hospital Anxiety and Depression (HAD) test, Dispositional optimism, Locus of control, the Subjective Stress Experience test (SSE) and the Stress-Energy (SE) test, were also derived. Marked effects due to affective personality type upon somatic and psychological stress, anxiety and depression, self-esteem, internal and external locus of control, optimism, stress and energy, intrinsic motivation, external regulation, identified regulation, major sleep problems, problems falling asleep, and psychophysiological problems were observed; levels of self-esteem, self-motivation and BDI-depression all produced substantial effects on health and well-being. Regression analyses indicated PA was predicted by dispositional optimism (thrice), energy (thrice), and intrinsic motivation, and counter predicted by depression (twice) and stress (twice); and NA by anxiety (twice), stress (twice), psychological stress, identified regulation, BDI depression and psychophysiological problems, and counter predicted by internal locus of control and self-esteem. BDI-depression was predicted by negative affect, major sleep problems and psychophysiological problems (Study III), self-esteem by dispositional optimism and energy, and counter predicted by anxiety, depression and stress (Study I), and intrinsic motivation by dispositional optimism, energy, PA and self-esteem (Study II). These convergent findings are interpreted from a perspective of the cognitive-emotional expressions underlying behavioural or presymptomatic profiles presenting predispositions for health or ill health.

Feeling powerless: Locus of control as a potential target for supportive care interventions to increase quality of life and decrease anxiety in ovarian cancer patients.

PubMed

Brown, Alaina J; Sun, Charlotte C; Urbauer, Diana L; Bodurka, Diane C; Thaker, Premal H; Ramondetta, Lois M

2015-08-01

To evaluate if an individual's locus of control (LOC) predicts various quality of life (QOL) and mental well-being measures. To identify targets that might enhance the overall spiritual well-being and QOL of ovarian cancer patients. Multi-site analysis of women with newly diagnosed stages II-IV ovarian, primary peritoneal or fallopian tube cancer. Patients completed the following surveys: Locus of Control Scale (LOC), Functional Assessment of Chronic Illness Therapy-Ovarian (FACT-O), Functional Assessment of Chronic Illness Therapy-Spiritual (FACIT-Sp), Edmonton Symptom Assessment score (ESAS), Hospital Anxiety Depression Scale (HADS), Templer's Death Anxiety Scale (DAS), and Herth Hope Index (HHI). Regression models were created to examine the effect of LOC upon QOL, symptoms, and other measures of mental well-being. These models adjusted for the effect of site of care, race, and partnership status as potential confounders. This study enrolled 104 patients from three separate treatment facilities. After adjusting for site, race and partnership status, higher levels of external LOC predicted decreased QOL (FACT-O) (p<0.05). Higher levels of external LOC also correlated with increased death anxiety and general anxiety (p≤0.05). Additionally, higher levels of external LOC predicted decreased hope (HHI) (p≤0.01). Ovarian cancer patients with a high external LOC may be at risk for decreased QOL at the time of their cancer diagnosis. They may also experience higher levels of anxiety and decreased feelings of hope. Identification of these women and interventions designed to increase a woman's sense of control over her situation may improve QOL and overall mental well-being. Copyright © 2015. Published by Elsevier Inc.

Fine-Mapping of the 1p11.2 Breast Cancer Susceptibility Locus

PubMed Central

Horne, Hisani N.; Chung, Charles C.; Zhang, Han; Yu, Kai; Prokunina-Olsson, Ludmila; Michailidou, Kyriaki; Bolla, Manjeet K.; Wang, Qin; Dennis, Joe; Hopper, John L.; Southey, Melissa C.; Schmidt, Marjanka K.; Broeks, Annegien; Muir, Kenneth; Lophatananon, Artitaya; Fasching, Peter A.; Beckmann, Matthias W.; Fletcher, Olivia; Johnson, Nichola; Sawyer, Elinor J.; Tomlinson, Ian; Burwinkel, Barbara; Marme, Frederik; Guénel, Pascal; Truong, Thérèse; Bojesen, Stig E.; Flyger, Henrik; Benitez, Javier; González-Neira, Anna; Anton-Culver, Hoda; Neuhausen, Susan L.; Brenner, Hermann; Arndt, Volker; Meindl, Alfons; Schmutzler, Rita K.; Brauch, Hiltrud; Hamann, Ute; Nevanlinna, Heli; Khan, Sofia; Matsuo, Keitaro; Iwata, Hiroji; Dörk, Thilo; Bogdanova, Natalia V.; Lindblom, Annika; Margolin, Sara; Mannermaa, Arto; Kosma, Veli-Matti; Chenevix-Trench, Georgia; Wu, Anna H.; ven den Berg, David; Smeets, Ann; Zhao, Hui; Chang-Claude, Jenny; Rudolph, Anja; Radice, Paolo; Barile, Monica; Couch, Fergus J.; Vachon, Celine; Giles, Graham G.; Milne, Roger L.; Haiman, Christopher A.; Marchand, Loic Le; Goldberg, Mark S.; Teo, Soo H.; Taib, Nur A. M.; Kristensen, Vessela; Borresen-Dale, Anne-Lise; Zheng, Wei; Shrubsole, Martha; Winqvist, Robert; Jukkola-Vuorinen, Arja; Andrulis, Irene L.; Knight, Julia A.; Devilee, Peter; Seynaeve, Caroline; García-Closas, Montserrat; Czene, Kamila; Darabi, Hatef; Hollestelle, Antoinette; Martens, John W. M.; Li, Jingmei; Lu, Wei; Shu, Xiao-Ou; Cox, Angela; Cross, Simon S.; Blot, William; Cai, Qiuyin; Shah, Mitul; Luccarini, Craig; Baynes, Caroline; Harrington, Patricia; Kang, Daehee; Choi, Ji-Yeob; Hartman, Mikael; Chia, Kee Seng; Kabisch, Maria; Torres, Diana; Jakubowska, Anna; Lubinski, Jan; Sangrajrang, Suleeporn; Brennan, Paul; Slager, Susan; Yannoukakos, Drakoulis; Shen, Chen-Yang; Hou, Ming-Feng; Swerdlow, Anthony; Orr, Nick; Simard, Jacques; Hall, Per; Pharoah, Paul D. P.

2016-01-01

The Cancer Genetic Markers of Susceptibility genome-wide association study (GWAS) originally identified a single nucleotide polymorphism (SNP) rs11249433 at 1p11.2 associated with breast cancer risk. To fine-map this locus, we genotyped 92 SNPs in a 900kb region (120,505,799–121,481,132) flanking rs11249433 in 45,276 breast cancer cases and 48,998 controls of European, Asian and African ancestry from 50 studies in the Breast Cancer Association Consortium. Genotyping was done using iCOGS, a custom-built array. Due to the complicated nature of the region on chr1p11.2: 120,300,000–120,505,798, that lies near the centromere and contains seven duplicated genomic segments, we restricted analyses to 429 SNPs excluding the duplicated regions (42 genotyped and 387 imputed). Per-allelic associations with breast cancer risk were estimated using logistic regression models adjusting for study and ancestry-specific principal components. The strongest association observed was with the original identified index SNP rs11249433 (minor allele frequency (MAF) 0.402; per-allele odds ratio (OR) = 1.10, 95% confidence interval (CI) 1.08–1.13, P = 1.49 x 10-21). The association for rs11249433 was limited to ER-positive breast cancers (test for heterogeneity P≤8.41 x 10-5). Additional analyses by other tumor characteristics showed stronger associations with moderately/well differentiated tumors and tumors of lobular histology. Although no significant eQTL associations were observed, in silico analyses showed that rs11249433 was located in a region that is likely a weak enhancer/promoter. Fine-mapping analysis of the 1p11.2 breast cancer susceptibility locus confirms this region to be limited to risk to cancers that are ER-positive. PMID:27556229

Fine-Mapping of the 1p11.2 Breast Cancer Susceptibility Locus.

PubMed

Horne, Hisani N; Chung, Charles C; Zhang, Han; Yu, Kai; Prokunina-Olsson, Ludmila; Michailidou, Kyriaki; Bolla, Manjeet K; Wang, Qin; Dennis, Joe; Hopper, John L; Southey, Melissa C; Schmidt, Marjanka K; Broeks, Annegien; Muir, Kenneth; Lophatananon, Artitaya; Fasching, Peter A; Beckmann, Matthias W; Fletcher, Olivia; Johnson, Nichola; Sawyer, Elinor J; Tomlinson, Ian; Burwinkel, Barbara; Marme, Frederik; Guénel, Pascal; Truong, Thérèse; Bojesen, Stig E; Flyger, Henrik; Benitez, Javier; González-Neira, Anna; Anton-Culver, Hoda; Neuhausen, Susan L; Brenner, Hermann; Arndt, Volker; Meindl, Alfons; Schmutzler, Rita K; Brauch, Hiltrud; Hamann, Ute; Nevanlinna, Heli; Khan, Sofia; Matsuo, Keitaro; Iwata, Hiroji; Dörk, Thilo; Bogdanova, Natalia V; Lindblom, Annika; Margolin, Sara; Mannermaa, Arto; Kosma, Veli-Matti; Chenevix-Trench, Georgia; Wu, Anna H; Ven den Berg, David; Smeets, Ann; Zhao, Hui; Chang-Claude, Jenny; Rudolph, Anja; Radice, Paolo; Barile, Monica; Couch, Fergus J; Vachon, Celine; Giles, Graham G; Milne, Roger L; Haiman, Christopher A; Marchand, Loic Le; Goldberg, Mark S; Teo, Soo H; Taib, Nur A M; Kristensen, Vessela; Borresen-Dale, Anne-Lise; Zheng, Wei; Shrubsole, Martha; Winqvist, Robert; Jukkola-Vuorinen, Arja; Andrulis, Irene L; Knight, Julia A; Devilee, Peter; Seynaeve, Caroline; García-Closas, Montserrat; Czene, Kamila; Darabi, Hatef; Hollestelle, Antoinette; Martens, John W M; Li, Jingmei; Lu, Wei; Shu, Xiao-Ou; Cox, Angela; Cross, Simon S; Blot, William; Cai, Qiuyin; Shah, Mitul; Luccarini, Craig; Baynes, Caroline; Harrington, Patricia; Kang, Daehee; Choi, Ji-Yeob; Hartman, Mikael; Chia, Kee Seng; Kabisch, Maria; Torres, Diana; Jakubowska, Anna; Lubinski, Jan; Sangrajrang, Suleeporn; Brennan, Paul; Slager, Susan; Yannoukakos, Drakoulis; Shen, Chen-Yang; Hou, Ming-Feng; Swerdlow, Anthony; Orr, Nick; Simard, Jacques; Hall, Per; Pharoah, Paul D P; Easton, Douglas F; Chanock, Stephen J; Dunning, Alison M; Figueroa, Jonine D

2016-01-01

The Cancer Genetic Markers of Susceptibility genome-wide association study (GWAS) originally identified a single nucleotide polymorphism (SNP) rs11249433 at 1p11.2 associated with breast cancer risk. To fine-map this locus, we genotyped 92 SNPs in a 900kb region (120,505,799-121,481,132) flanking rs11249433 in 45,276 breast cancer cases and 48,998 controls of European, Asian and African ancestry from 50 studies in the Breast Cancer Association Consortium. Genotyping was done using iCOGS, a custom-built array. Due to the complicated nature of the region on chr1p11.2: 120,300,000-120,505,798, that lies near the centromere and contains seven duplicated genomic segments, we restricted analyses to 429 SNPs excluding the duplicated regions (42 genotyped and 387 imputed). Per-allelic associations with breast cancer risk were estimated using logistic regression models adjusting for study and ancestry-specific principal components. The strongest association observed was with the original identified index SNP rs11249433 (minor allele frequency (MAF) 0.402; per-allele odds ratio (OR) = 1.10, 95% confidence interval (CI) 1.08-1.13, P = 1.49 x 10-21). The association for rs11249433 was limited to ER-positive breast cancers (test for heterogeneity P≤8.41 x 10-5). Additional analyses by other tumor characteristics showed stronger associations with moderately/well differentiated tumors and tumors of lobular histology. Although no significant eQTL associations were observed, in silico analyses showed that rs11249433 was located in a region that is likely a weak enhancer/promoter. Fine-mapping analysis of the 1p11.2 breast cancer susceptibility locus confirms this region to be limited to risk to cancers that are ER-positive.

Nothing left to chance? The impact of locus of control on physical and mental quality of life in terminal cancer patients.

PubMed

Brown, Alaina J; Thaker, Premal H; Sun, Charlotte C; Urbauer, Diana L; Bruera, Eduardo; Bodurka, Diane C; Ramondetta, Lois M

2017-06-01

The purpose of this study is to evaluate if locus of control (LOC) predicts various quality of life (QOL) and mental well-being measures among terminally ill cancer patients at the time of palliative care consult. Multi-site analysis of patients with advanced cancer being seen as new patients in a Palliative and Supportive Care outpatient clinic. Patients completed the following surveys: locus of control (LOC) scale, Functional Assessment of Chronic Illness Therapy-General (FACT-G), Functional Assessment of Chronic Illness Therapy-Spiritual (FACIT-Sp), Hospital Anxiety Depression Scale (HADS), and Herth Hope Index (HHI). Regression models were created to examine the effect of LOC upon QOL, symptoms, and other measures of mental well-being. These models adjusted for the effect of age, gender, race, partnership status, education, and months since diagnosis as potential confounders. This study enrolled 100 patients. After adjusting for site, race, and partnership status, higher levels of LOC chance predicted decreased QOL (FACT-G) (p < 0.01). Higher levels of LOC chance also correlated with increased depression and anxiety (p ≤ 0.01) and decreased meaning/peace and faith (p ≤ 0.01). Additionally, higher levels of LOC chance predicted decreased hope (HHI) (p ≤ 0.001). Terminally ill cancer patients with a high LOC chance may be at risk for decreased physical and mental well-being at the end of life. Efforts should be made to identify these patients and design interventions to increase their feeling of control over the situation in order to improve physical and mental well-being at the end of life.

Subcultural Determinants of Locus of Control (IE) Development. A Locus of Control (IE) Measure for Preschool-Age Children: Model, Method, and Validity.

ERIC Educational Resources Information Center

Stephens, Mark; Delys, Pamela

Both papers are concerned with locus of control (of reinforcement) expectancies among young children, especially preschoolers. The first reviews a number of studies which examined the relationship between locus of control, socioeconomic status, and ethnicity. The results indicate that (1) economic status is consistently related to locus of…

The multi-line slope method for measuring the effective magnetic field of cool stars: an application to the solar-like cycle of ɛ Eri

NASA Astrophysics Data System (ADS)

Scalia, C.; Leone, F.; Gangi, M.; Giarrusso, M.; Stift, M. J.

2017-12-01

One method for the determination of integrated longitudinal stellar fields from low-resolution spectra is the so-called slope method, which is based on the regression of the Stokes V signal against the first derivative of Stokes I. Here we investigate the possibility of extending this technique to measure the magnetic fields of cool stars from high-resolution spectra. For this purpose we developed a multi-line modification to the slope method, called the multi-line slope method. We tested this technique by analysing synthetic spectra computed with the COSSAM code and real observations obtained with the high-resolution spectropolarimeters Narval, HARPSpol and the Catania Astrophysical Observatory Spectropolarimeter (CAOS). We show that the multi-line slope method is a fast alternative to the least squares deconvolution technique for the measurement of the effective magnetic fields of cool stars. Using a Fourier transform on the effective magnetic field variations of the star ε Eri, we find that the long-term periodicity of the field corresponds to the 2.95-yr period of the stellar dynamo, revealed by the variation of the activity index.

A Novel Method for Age Estimation in Solar-Type Stars Through GALEX FUV Magnitudes

NASA Astrophysics Data System (ADS)

Ho, Kelly; Subramonian, Arjun; Smith, Graeme; Shouru Shieh

2018-01-01

Utilizing an inverse association known to exist between Galaxy Evolution Explorer (GALEX) far ultraviolet (FUV) magnitudes and the chromospheric activity of F, G, and K dwarfs, we explored a method of age estimation in solar-type stars through GALEX FUV magnitudes. Sample solar-type star data were collected from refereed publications and filtered by B-V and absolute visual magnitude to ensure similarities in temperature and luminosity to the Sun. We determined FUV-B and calculated a residual index Q for all the stars, using the temperature-induced upper bound on FUV-B as the fiducial. Plotting current age estimates for the stars against Q, we discovered a strong and significant association between the variables. By applying a log-linear transformation to the data to produce a strong correlation between Q and loge Age, we confirmed the association between Q and age to be exponential. Thus, least-squares regression was used to generate an exponential model relating Q to age in solar-type stars, which can be used by astronomers. The Q-method of stellar age estimation is simple and more efficient than existing spectroscopic methods and has applications to galactic archaeology and stellar chemical composition analysis.

Predictors of yoga use among internal medicine patients.

PubMed

Cramer, Holger; Lauche, Romy; Langhorst, Jost; Paul, Anna; Michalsen, Andreas; Dobos, Gustav

2013-07-13

Yoga seems to be an effective means to cope with a variety of internal medicine conditions. While characteristics of yoga users have been investigated in the general population, little is known about predictors of yoga use and barriers to yoga use in internal medicine patients. The aim of this cross-sectional analysis was to identify sociodemographic, clinical, and psychological predictors of yoga use among internal medicine patients. A cross-sectional analysis was conducted among all patients being referred to a Department of Internal and Integrative Medicine during a 3-year period. It was assessed whether patients had ever used yoga for their primary medical complaint, the perceived benefit, and the perceived harm of yoga practice. Potential predictors of yoga use including sociodemographic characteristics, health behavior, internal medicine diagnosis, general health status, mental health, satisfaction with health, and health locus of control were assessed; and associations with yoga use were tested using multiple logistic regression analysis. Odds ratios (OR) with 95% confidence intervals (CI) were calculated for significant predictors. Of 2486 participants, 303 (12.19%) reported having used yoga for their primary medical complaint. Of those, 184 (60.73%) reported benefits and 12 (3.96%) reported harms due to yoga practice. Compared to yoga non-users, yoga users were more likely to be 50-64 years old (OR = 1.45; 95%CI = 1.05-2.01; P = 0.025); female (OR = 2.45; 95%CI = 1.45-4.02; P < 0.001); and college graduates (OR = 1.61; 95%CI = 1.14-2.27; P = 0.007); and less likely to currently smoke (OR = 0.61; 95%CI = 0.39-0.96; P = 0.031). Manifest anxiety (OR = 1.47; 95%CI = 1.06-2.04; P = 0.020); and high internal health locus of control (OR = 1.92; 95%CI = 1.38-2.67; P < 0.001) were positively associated with yoga use, while high external-fatalistic health locus of control (OR = 0.66; 95%CI = 0.47-0.92; P = 0.014) was negatively associated with yoga use. Yoga was used for their primary medical complaint by 12.19% of an internal integrative medicine patient population and was commonly perceived as beneficial. Yoga use was not associated with the patients' specific diagnosis but with sociodemographic factors, mental health, and health locus of control. To improve adherence to yoga practice, it should be considered that male, younger, and anxious patients and those with low internal health locus of control might be less intrinsically motivated to start yoga.

Two-locus diseas models with two marker loci: The power of affected-sib-pair tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knapp, M.; Seuchter, S.A.; Bauer, M.P.

1994-11-01

Recently, Schork et al. found that two-trait-locus, two-marker-locus (parametric) linkage analysis can provide substantially more linkage information than can standard one-trait-locus, one-marker-locus methods. However, because of the increased burden of computation, Schork et al. do not expect that their approach will be applied in an initial genome scan. Further, the specification of a suitable two-locus segregation model can be crucial. Affected-sib-pair tests are computationally simple and do not require an explicit specification of the disease model. In the past, however, these tests mainly have been applied to data with a single marker locus. Here, we consider sib-pair tests that makemore » it possible to analyze simultaneously two marker loci. The power of these tests is investigated for different (epistatic and heterogeneous) two-trait-locus models, each trait locus being linked to one of the marker loci. We compare these tests both with the test that is optimal for a certain model and with the strategy that analyzes each marker locus separately. The results indicate that a straightforward extension of the well-known mean test for two marker loci can be much more powerful than single-marker-locus analysis and that its power is only slightly inferior to the power of the optimal test. 21 refs., 5 figs., 2 tabs.« less

An ultra-faint galaxy candidate discovered in early data from the Magellanic Satellites Survey

DOE PAGES

Drlica-Wagner, A.; Bechtol, Keith; Allam, S.; ...

2016-11-30

Here, we report a new ultra-faint stellar system found in Dark Energy Camera data from the first observing run of the Magellanic Satellites Survey (MagLiteS). MagLiteS J0644–5953 (Pictor II or Pic II) is a low surface brightness (more » $$\\mu ={28.5}_{-1}^{+1}\\,\\mathrm{mag}\\,\\,\\mathrm{arcsec}{}^{-2}$$ within its half-light radius) resolved overdensity of old and metal-poor stars located at a heliocentric distance of $${45}_{-4}^{+5}\\,\\mathrm{kpc}$$. The physical size ($${r}_{1/2}={46}_{-11}^{+15}\\,\\mathrm{pc}\\,$$) and low luminosity ($${M}_{V}=-{3.2}_{-0.5}^{+0.4}\\,\\mathrm{mag}\\,$$) of this satellite are consistent with the locus of spectroscopically confirmed ultra-faint galaxies. MagLiteS J0644–5953 (Pic II) is located $${11.3}_{-0.9}^{+3.1}\\,\\mathrm{kpc}\\,$$ from the Large Magellanic Cloud (LMC), and comparisons with simulation results in the literature suggest that this satellite was likely accreted with the LMC. The close proximity of MagLiteS J0644–5953 (Pic II) to the LMC also makes it the most likely ultra-faint galaxy candidate to still be gravitationally bound to the LMC.« less

An ultra-faint galaxy candidate discovered in early data from the Magellanic Satellites Survey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drlica-Wagner, A.; Bechtol, Keith; Allam, S.

Here, we report a new ultra-faint stellar system found in Dark Energy Camera data from the first observing run of the Magellanic Satellites Survey (MagLiteS). MagLiteS J0644–5953 (Pictor II or Pic II) is a low surface brightness (more » $$\\mu ={28.5}_{-1}^{+1}\\,\\mathrm{mag}\\,\\,\\mathrm{arcsec}{}^{-2}$$ within its half-light radius) resolved overdensity of old and metal-poor stars located at a heliocentric distance of $${45}_{-4}^{+5}\\,\\mathrm{kpc}$$. The physical size ($${r}_{1/2}={46}_{-11}^{+15}\\,\\mathrm{pc}\\,$$) and low luminosity ($${M}_{V}=-{3.2}_{-0.5}^{+0.4}\\,\\mathrm{mag}\\,$$) of this satellite are consistent with the locus of spectroscopically confirmed ultra-faint galaxies. MagLiteS J0644–5953 (Pic II) is located $${11.3}_{-0.9}^{+3.1}\\,\\mathrm{kpc}\\,$$ from the Large Magellanic Cloud (LMC), and comparisons with simulation results in the literature suggest that this satellite was likely accreted with the LMC. The close proximity of MagLiteS J0644–5953 (Pic II) to the LMC also makes it the most likely ultra-faint galaxy candidate to still be gravitationally bound to the LMC.« less

Reevaluating Old Stellar Populations

NASA Astrophysics Data System (ADS)

Stanway, E. R.; Eldridge, J. J.

2018-05-01

Determining the properties of old stellar populations (those with age >1 Gyr) has long involved the comparison of their integrated light, either in the form of photometry or spectroscopic indexes, with empirical or synthetic templates. Here we reevaluate the properties of old stellar populations using a new set of stellar population synthesis models, designed to incorporate the effects of binary stellar evolution pathways as a function of stellar mass and age. We find that single-aged stellar population models incorporating binary stars, as well as new stellar evolution and atmosphere models, can reproduce the colours and spectral indices observed in both globular clusters and quiescent galaxies. The best fitting model populations are often younger than those derived from older spectral synthesis models, and may also lie at slightly higher metallicities.

Estimating stellar effective temperatures and detected angular parameters using stochastic particle swarm optimization

NASA Astrophysics Data System (ADS)

Zhang, Chuan-Xin; Yuan, Yuan; Zhang, Hao-Wei; Shuai, Yong; Tan, He-Ping

2016-09-01

Considering features of stellar spectral radiation and sky surveys, we established a computational model for stellar effective temperatures, detected angular parameters and gray rates. Using known stellar flux data in some bands, we estimated stellar effective temperatures and detected angular parameters using stochastic particle swarm optimization (SPSO). We first verified the reliability of SPSO, and then determined reasonable parameters that produced highly accurate estimates under certain gray deviation levels. Finally, we calculated 177 860 stellar effective temperatures and detected angular parameters using data from the Midcourse Space Experiment (MSX) catalog. These derived stellar effective temperatures were accurate when we compared them to known values from literatures. This research makes full use of catalog data and presents an original technique for studying stellar characteristics. It proposes a novel method for calculating stellar effective temperatures and detecting angular parameters, and provides theoretical and practical data for finding information about radiation in any band.

Color-Space Outliers in DPOSS: Quasars and Peculiar Objects

NASA Astrophysics Data System (ADS)

Djorgovski, S. G.; Gal, R. R.; Mahabal, A.; Brunner, R.; Castro, S. M.; Odewahn, S. C.; de Carvalho, R. R.; DPOSS Team

2000-12-01

The processing of DPOSS, a digital version of the POSS-II sky atlas, is now nearly complete. The resulting Palomar--Norris Sky Catalog (PNSC) is expected to contain > 5 x 107 galaxies and > 109 stars, including large numbers of quasars and other unresolved sources. For objects morphologically classified as stellar (i.e., PSF-like), colors and magnitudes provide the only additional source of discriminating information. We investigate the distribution of objects in the parameter space of (g-r) and (r-i) colors as a function of magnitude. Normal stars form a well-defined (temperature) sequence in this parameter space, and we explore the nature of the objects which deviate significantly from this stellar locus. The causes of the deviations include: non-thermal or peculiar spectra, interagalactic absorption (for high-z quasars), presence of strong emission lines in one or more of the bandpasses, or strong variability (because the plates are taken at widely separated epochs). In addition to minor contamination by misclassified compact galaxies, we find the following: (1) Quasars at z > 4; to date, ~ 100 of these objects have been found, and used for a variety of follow-up studies. They are made publicly available immediately after discovery, through http://astro.caltech.edu/ ~george/z4.qsos. (2) Type-2 quasars in the redshift interval z ~ 0.31 - 0.38. (3) Other quasars, starburst and emission-line galaxies, and emission-line stars. (4) Objects with highly peculiar spectra, some or all of which may be rare subtypes of BAL QSOs. (5) Highly variable stars and optical transients, some of which may be GRB ``orphan afterglows''. To date, systematic searches have been made only for (1) and (2); other types of objects were found serendipitously. However, we plan to explore systematically all of the statistically significant outliers in this parameter space. This illustrates the potential of large digital sky surveys for discovery of rare types of objects, both known (e.g., high-z quasars) and as yet unknown.

The Solar Neighborhood. XXXII. The Hydrogen Burning Limit

NASA Astrophysics Data System (ADS)

Dieterich, Sergio B.; Henry, Todd J.; Jao, Wei-Chun; Winters, Jennifer G.; Hosey, Altonio D.; Riedel, Adric R.; Subasavage, John P.

2014-05-01

We construct a Hertzsprung-Russell diagram for the stellar/substellar boundary based on a sample of 63 objects ranging in spectral type from M6V to L4. We report newly observed VRI photometry for all 63 objects and new trigonometric parallaxes for 37 objects. The remaining 26 objects have trigonometric parallaxes from the literature. We combine our optical photometry and trigonometric parallaxes with 2MASS and WISE photometry and employ a novel spectral energy distribution fitting algorithm to determine effective temperatures, bolometric luminosities, and radii. Our uncertainties range from ~20 K to ~150 K in temperature, ~0.01 to ~0.06 in log (L/L ⊙) and ~3% to ~10% in radius. We check our methodology by comparing our calculated radii to radii directly measured via long baseline optical interferometry. We find evidence for the local minimum in the radius-temperature and radius-luminosity trends that signals the end of the stellar main sequence and the start of the brown dwarf sequence at T eff ~ 2075 K, log (L/L ⊙) ~ -3.9, and (R/R ⊙) ~ 0.086. The existence of this local minimum is predicted by evolutionary models, but at temperatures ~400 K cooler. The minimum radius happens near the locus of 2MASS J0523-1403, an L2.5 dwarf with V - K = 9.42. We make qualitative arguments as to why the effects of the recent revision in solar abundances accounts for the discrepancy between our findings and the evolutionary models. We also report new color-absolute magnitude relations for optical and infrared colors which are useful for estimating photometric distances. We study the optical variability of all 63 targets and find an overall variability fraction of 36^{+9}_{-7}% at a threshold of 15 mmag in the I band, which is in agreement with previous studies.

Are math readiness and personality predictive of first-year retention in engineering?

PubMed

Moses, Laurie; Hall, Cathy; Wuensch, Karl; De Urquidi, Karen; Kauffmann, Paul; Swart, William; Duncan, Steve; Dixon, Gene

2011-01-01

On the basis of J. G. Borkowski, L. K. Chan, and N. Muthukrishna's model of academic success (2000), the present authors hypothesized that freshman retention in an engineering program would be related to not only basic aptitude but also affective factors. Participants were 129 college freshmen with engineering as their stated major. Aptitude was measured by SAT verbal and math scores, high school grade-point average (GPA), and an assessment of calculus readiness. Affective factors were assessed by the NEO-Five Factor Inventory (FFI; P. I. Costa & R. R. McCrae, 2007), and the Nowicki-Duke Locus of Control (LOC) scale (S. Nowicki & M. Duke, 1974). A binary logistic regression analysis found that calculus readiness and high school GPA were predictive of retention. Scores on the Neuroticism and Openness subscales from the NEO-FFI and LOC were correlated with retention status, but Openness was the only affective factor with a significant unique effect in the binary logistic regression. Results of the study lend modest support to Borkowski's model.

Estimating precise metallicity and stellar mass evolution of galaxies

NASA Astrophysics Data System (ADS)

Mosby, Gregory

2018-01-01

The evolution of galaxies can be conveniently broken down into the evolution of their contents. The changing dust, gas, and stellar content in addition to the changing dark matter potential and periodic feedback from a super-massive blackhole are some of the key ingredients. We focus on the stellar content that can be observed, as the stars reflect information about the galaxy when they were formed. We approximate the stellar content and star formation histories of unresolved galaxies using stellar population modeling. Though simplistic, this approach allows us to reconstruct the star formation histories of galaxies that can be used to test models of galaxy formation and evolution. These models, however, suffer from degeneracies at large lookback times (t > 1 Gyr) as red, low luminosity stars begin to dominate a galaxy’s spectrum. Additionally, degeneracies between stellar populations at different ages and metallicities often make stellar population modeling less precise. The machine learning technique diffusion k-means has been shown to increase the precision in stellar population modeling using a mono-metallicity basis set. However, as galaxies evolve, we expect the metallicity of stellar populations to vary. We use diffusion k-means to generate a multi-metallicity basis set to estimate the stellar mass and chemical evolution of unresolved galaxies. Two basis sets are formed from the Bruzual & Charlot 2003 and MILES stellar population models. We then compare the accuracy and precision of these models in recovering complete (stellar mass and metallicity) histories of mock data. Similarities in the groupings of stellar population spectra in the diffusion maps for each metallicity hint at fundamental age transitions common to both basis sets that can be used to identify stellar populations in a given age range.

The locus control region is required for association of the murine β-globin locus with engaged transcription factories during erythroid maturation

PubMed Central

Ragoczy, Tobias; Bender, M.A.; Telling, Agnes; Byron, Rachel; Groudine, Mark

2006-01-01

We have examined the relationship between nuclear localization and transcriptional activity of the endogenous murine β-globin locus during erythroid differentiation. Murine fetal liver cells were separated into distinct erythroid maturation stages by fluorescence-activated cell sorting, and the nuclear position of the locus was determined at each stage. We find that the β-globin locus progressively moves away from the nuclear periphery with increasing maturation. Contrary to the prevailing notion that the nuclear periphery is a repressive compartment in mammalian cells, βmajor-globin expression begins at the nuclear periphery prior to relocalization. However, relocation of the locus to the nuclear interior with maturation is accompanied by an increase in βmajor-globin transcription. The distribution of nuclear polymerase II (Pol II) foci also changes with erythroid differentiation: Transcription factories decrease in number and contract toward the nuclear interior. Moreover, both efficient relocalization of the β-globin locus from the periphery and its association with hyperphosphorylated Pol II transcription factories require the locus control region (LCR). These results suggest that the LCR-dependent association of the β-globin locus with transcriptionally engaged Pol II foci provides the driving force for relocalization of the locus toward the nuclear interior during erythroid maturation. PMID:16705039

Reconstruction of magnetic configurations in W7-X using artificial neural networks

NASA Astrophysics Data System (ADS)

Böckenhoff, Daniel; Blatzheim, Marko; Hölbe, Hauke; Niemann, Holger; Pisano, Fabio; Labahn, Roger; Pedersen, Thomas Sunn; The W7-X Team

2018-05-01

It is demonstrated that artificial neural networks can be used to accurately and efficiently predict details of the magnetic topology at the plasma edge of the Wendelstein 7-X stellarator, based on simulated as well as measured heat load patterns onto plasma-facing components observed with infrared cameras. The connection between heat load patterns and the magnetic topology is a challenging regression problem, but one that suits artificial neural networks well. The use of a neural network makes it feasible to analyze and control the plasma exhaust in real-time, an important goal for Wendelstein 7-X, and for magnetic confinement fusion research in general.

THE OBSERVED RELATION BETWEEN STELLAR MASS, DUST EXTINCTION, AND STAR FORMATION RATE IN LOCAL GALAXIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zahid, H. J.; Kewley, L. J.; Kudritzki, R. P.

In this study, we investigate the relation between stellar mass, dust extinction, and star formation rate (SFR) using {approx}150,000 star-forming galaxies from SDSS DR7. We show that the relation between dust extinction and SFR changes with stellar mass. For galaxies at the same stellar mass, dust extinction is anti-correlated with the SFR at stellar masses <10{sup 10} M {sub Sun }. There is a sharp transition in the relation at a stellar mass of 10{sup 10} M {sub Sun }. At larger stellar masses, dust extinction is positively correlated with the SFR for galaxies at the same stellar mass. Themore » observed relation between stellar mass, dust extinction, and SFR presented in this study helps to confirm similar trends observed in the relation between stellar mass, metallicity, and SFR. The relation reported in this study provides important new constraints on the physical processes governing the chemical evolution of galaxies. The correlation between SFR and dust extinction for galaxies with stellar masses >10{sup 10} M {sub Sun} is shown to extend to the population of quiescent galaxies suggesting that the physical processes responsible for the observed relation between stellar mass, dust extinction, and SFR may be related to the processes leading to the shutdown of star formation in galaxies.« less

The masses and metallicities of stellar haloes reflect galactic merger histories

NASA Astrophysics Data System (ADS)

D'Souza, Richard; Bell, Eric F.

2018-03-01

There is increasing observational and theoretical evidence for a correlation between the metallicity and the mass of the stellar halo for galaxies with Milky Way-like stellar masses. Using the Illustris cosmological hydrodynamical simulations, we find that this relationship arises because a single massive progenitor contributes the bulk of the mass to the accreted stellar component as well as sets its metallicity. Moreover, in the Illustris simulations, this relationship extends over 3 orders of magnitude in accreted stellar mass for central galaxies. We show that for Milky Way-like mass galaxies, the scatter in accreted metallicity at a fixed accreted stellar mass encodes information about the stellar mass of the dominant accreted progenitor, while the radial density and metallicity gradients of the accreted stellar component encodes information about the time of accretion of the dominant progenitor. We demonstrate that for Milky Way-like mass galaxies, the Illustris simulations predict that the metallicity and the stellar mass of the total accreted stellar component can be reconstructed from aperture measurements of the stellar halo along the minor axis of edge-on disc galaxies. These correlations highlight the potential for observational studies of stellar haloes to quantify our understanding of the most dominant events in the growth history of galaxies. We explore the implications of our model for our understanding of the accretion histories of the Milky Way, M31, and NGC 5128. In particular, a relatively late and massive accretion is favoured for M31; additionally, we provide a first estimate of the accreted stellar mass for NGC 5128.

Validation: Codes to compare simulation data to various observations

NASA Astrophysics Data System (ADS)

Cohn, J. D.

2017-02-01

Validation provides codes to compare several observations to simulated data with stellar mass and star formation rate, simulated data stellar mass function with observed stellar mass function from PRIMUS or SDSS-GALEX in several redshift bins from 0.01-1.0, and simulated data B band luminosity function with observed stellar mass function, and to create plots for various attributes, including stellar mass functions, and stellar mass to halo mass. These codes can model predictions (in some cases alongside observational data) to test other mock catalogs.

The relationship between the INTERMED patient complexity instrument and Level of Care Utilisation System (LOCUS).

PubMed

Thurber, Steven; Wilson, Ann; Realmuto, George; Specker, Sheila

2018-03-01

To investigate the concurrent and criterion validity of two independently developed measurement instruments, INTERMED and LOCUS, designed to improve the treatment and clinical management of patients with complex symptom manifestations. Participants (N = 66) were selected from hospital records based on the complexity of presenting symptoms, with tripartite diagnoses across biological, psychiatric and addiction domains. Biopsychosocial information from hospital records were submitted to INTERMED and LOCUS grids. In addition, Global Assessment of Functioning (GAF) ratings were gathered for statistical analyses. The product moment correlation between INTERMED and LOCUS was 0.609 (p = .01). Inverse zero-order correlations for INTERMED and LOCUS total score and GAF were obtained. However, only the beta weight for LOCUS and GAF was significant. An exploratory principal components analysis further illuminated areas of convergence between the instruments. INTERMED and LOCUS demonstrated shared variance. INTERMED appeared more sensitive to complex medical conditions and severe physiological reactions, whereas LOCUS findings are more strongly related to psychiatric symptoms. Implications are discussed.

The California- Kepler Survey. II. Precise Physical Properties of 2025 Kepler Planets and Their Host Stars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, John Asher; Cargile, Phillip A.; Sinukoff, Evan

We present stellar and planetary properties for 1305 Kepler Objects of Interest hosting 2025 planet candidates observed as part of the California- Kepler Survey. We combine spectroscopic constraints, presented in Paper I, with stellar interior modeling to estimate stellar masses, radii, and ages. Stellar radii are typically constrained to 11%, compared to 40% when only photometric constraints are used. Stellar masses are constrained to 4%, and ages are constrained to 30%. We verify the integrity of the stellar parameters through comparisons with asteroseismic studies and Gaia parallaxes. We also recompute planetary radii for 2025 planet candidates. Because knowledge of planetarymore » radii is often limited by uncertainties in stellar size, we improve the uncertainties in planet radii from typically 42% to 12%. We also leverage improved knowledge of stellar effective temperature to recompute incident stellar fluxes for the planets, now precise to 21%, compared to a factor of two when derived from photometry.« less

Unbound Young Stellar Systems: Star Formation on the Loose

NASA Astrophysics Data System (ADS)

Gouliermis, Dimitrios A.

2018-07-01

Unbound young stellar systems, the loose ensembles of physically related young bright stars, trace the typical regions of recent star formation in galaxies. Their morphologies vary from small few pc-size associations of newly formed stars to enormous few kpc-size complexes composed of stars few 100 Myr old. These stellar conglomerations are located within the disks and along the spiral arms and rings of star-forming disk galaxies, and they are the active star-forming centers of dwarf and starburst galaxies. Being associated with star-forming regions of various sizes, these stellar structures trace the regions where stars form at various length- and timescales, from compact clusters to whole galactic disks. Stellar associations, the prototypical unbound young systems, and their larger counterparts, stellar aggregates, and stellar complexes, have been the focus of several studies for quite a few decades, with special interest on their demographics, classification, and structural morphology. The compiled surveys of these loose young stellar systems demonstrate that the clear distinction of these systems into well-defined classes is not as straightforward as for stellar clusters, due to their low densities, asymmetric shapes and variety in structural parameters. These surveys also illustrate that unbound stellar structures follow a clear hierarchical pattern in the clustering of their stars across various scales. Stellar associations are characterized by significant sub-structure with bound stellar clusters being their most compact parts, while associations themselves are the brighter denser parts of larger stellar aggregates and stellar complexes, which are members of larger super-structures up to the scale of a whole star-forming galaxy. This structural pattern, which is usually characterized as self-similar or fractal, appears to be identical to that of star-forming giant molecular clouds and interstellar gas, driven mainly by turbulence cascade. In this short review, I make a concise compilation of our understanding of unbound young stellar systems across various environments in the local universe, as it is developed during the last 60 years. I present a factual assessment of the clustering behavior of star formation, as revealed from the assembling pattern of stars across loose stellar structures and its relation to the interstellar medium and the environmental conditions. I also provide a consistent account of the processes that possibly play important role in the formation of unbound stellar systems, compiled from both theoretical and observational investigations on the field.

Stellar Populations. A User Guide from Low to High Redshift

NASA Astrophysics Data System (ADS)

Greggio, Laura; Renzini, Alvio

2011-09-01

This textbook is meant to illustrate the specific role played by stellar population diagnostics in our attempt to understand galaxy formation and evolution. The book starts with a rather unconventional summary of the results of stellar evolution theory (Chapter 1), as they provide the basis for the construction of synthetic stellar populations. Current limitations of stellar models are highlighted, which arise from the necessity to parametrize all those physical processes that involve bulk mass motions, such as convection, mixing, mass loss, etc. Chapter 2 deals with the foundations of the theory of synthetic stellar populations, and illustrates their energetics and metabolic functions, providing basic tools that will be used in subsequent chapters. Chapters 3 and 4 deal with resolved stellar populations, first addressing some general problems encountered in photometric studies of stellar fields. Then some highlights are presented illustrating our current capacity of measuring stellar ages in Galactic globular clusters, in the Galactic bulge and in nearby galaxies. Chapter 5 is dedicated to the exemplification of synthetic spectra of simple as well as composite stellar populations, drawing attention to those spectral features that may depend on less secure results of stellar evolution models. Chapter 6 illustrates how synthetic stellar populations are used to derive basic galaxy properties, such as star formation rates, stellar masses, ages and metallicities, and does so for galaxies at low as well as at high redshifts. Chapter 7 is dedicated to supernovae, distinguishing them in core collapse and thermonuclear cases, describing the evolution of their rates for various star formation histories, and estimating the supernova productivity of stellar populations and their chemical yields. In Chapter 8 the stellar initial mass function (IMF) is discussed, first showing how even apparently small IMF variations may have large effects on the demo! graphy of stellar populations, and then using galaxies at low ! and high redshifts and clusters of galaxies to set tight constraints on possible IMF variations in space or time. In Chapter 9 a phenomenological model of galaxy evolution is presented which illustrates a concrete application of the stellar population tools described in the previous chapters. Finally, Chapter 10 is dedicated to the chemical evolution on the scale of galaxies, clusters of galaxies and the whole Universe.

Corticotropin-Releasing Factor Mediates Pain-Induced Anxiety through the ERK1/2 Signaling Cascade in Locus Coeruleus Neurons

PubMed Central

Borges, Gisela Patrícia; Micó, Juan Antonio; Neto, Fani Lourença

2015-01-01

Background: The corticotropin-releasing factor is a stress-related neuropeptide that modulates locus coeruleus activity. As locus coeruleus has been involved in pain and stress-related patologies, we tested whether the pain-induced anxiety is a result of the corticotropin-releasing factor released in the locus coeruleus. Methods: Complete Freund’s adjuvant-induced monoarthritis was used as inflammatory chronic pain model. α-Helical corticotropin-releasing factor receptor antagonist was microinjected into the contralateral locus coeruleus of 4-week-old monoarthritic animals. The nociceptive and anxiety-like behaviors, as well as phosphorylated extracellular signal-regulated kinases 1/2 and corticotropin-releasing factor receptors expression, were quantified in the paraventricular nucleus and locus coeruleus. Results: Monoarthritic rats manifested anxiety and increased phosphorylated extracellular signal-regulated kinases 1/2 levels in the locus coeruleus and paraventricular nucleus, although the expression of corticotropin-releasing factor receptors was unaltered. α-Helical corticotropin-releasing factor antagonist administration reversed both the anxiogenic-like behavior and the phosphorylated extracellular signal-regulated kinases 1/2 levels in the locus coeruleus. Conclusions: Pain-induced anxiety is mediated by corticotropin-releasing factor neurotransmission in the locus coeruleus through extracellular signal-regulated kinases 1/2 signaling cascade. PMID:25716783

Stellar Streams Discovered in the Dark Energy Survey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shipp, N.; et al.

We perform a search for stellar streams around the Milky Way using the first three years of multi-band optical imaging data from the Dark Energy Survey (DES). We use DES data coveringmore » $$\\sim 5000$$ sq. deg. to a depth of $g > 23.5$ with a relative photometric calibration uncertainty of $$< 1 \\%$$. This data set yields unprecedented sensitivity to the stellar density field in the southern celestial hemisphere, enabling the detection of faint stellar streams to a heliocentric distance of $$\\sim 50$$ kpc. We search for stellar streams using a matched-filter in color-magnitude space derived from a synthetic isochrone of an old, metal-poor stellar population. Our detection technique recovers four previously known thin stellar streams: Phoenix, ATLAS, Tucana III, and a possible extension of Molonglo. In addition, we report the discovery of eleven new stellar streams. In general, the new streams detected by DES are fainter, more distant, and lower surface brightness than streams detected by similar techniques in previous photometric surveys. As a by-product of our stellar stream search, we find evidence for extra-tidal stellar structure associated with four globular clusters: NGC 288, NGC 1261, NGC 1851, and NGC 1904. The ever-growing sample of stellar streams will provide insight into the formation of the Galactic stellar halo, the Milky Way gravitational potential, as well as the large- and small-scale distribution of dark matter around the Milky Way.« less

Influence of Stellar Multiplicity On Planet Formation. III. Adaptive Optics Imaging of Kepler Stars With Gas Giant Planets

NASA Astrophysics Data System (ADS)

Wang, Ji; Fischer, Debra A.; Horch, Elliott P.; Xie, Ji-Wei

2015-06-01

As hundreds of gas giant planets have been discovered, we study how these planets form and evolve in different stellar environments, specifically in multiple stellar systems. In such systems, stellar companions may have a profound influence on gas giant planet formation and evolution via several dynamical effects such as truncation and perturbation. We select 84 Kepler Objects of Interest (KOIs) with gas giant planet candidates. We obtain high-angular resolution images using telescopes with adaptive optics (AO) systems. Together with the AO data, we use archival radial velocity data and dynamical analysis to constrain the presence of stellar companions. We detect 59 stellar companions around 40 KOIs for which we develop methods of testing their physical association. These methods are based on color information and galactic stellar population statistics. We find evidence of suppressive planet formation within 20 AU by comparing stellar multiplicity. The stellar multiplicity rate (MR) for planet host stars is {0}-0+5% within 20 AU. In comparison, the stellar MR is 18% ± 2% for the control sample, i.e., field stars in the solar neighborhood. The stellar MR for planet host stars is 34% ± 8% for separations between 20 and 200 AU, which is higher than the control sample at 12% ± 2%. Beyond 200 AU, stellar MRs are comparable between planet host stars and the control sample. We discuss the implications of the results on gas giant planet formation and evolution.

Velocity structure in long period variable star atmospheres

NASA Technical Reports Server (NTRS)

Pilachowski, C.; Wallerstein, G.; Willson, L. A.

1980-01-01

A regression analysis of the dependence of absorption line velocities on wavelength, line strength, excitation potential, and ionization potential is presented. The method determines the region of formation of the absorption lines for a given data and wavelength region. It is concluded that the scatter which is frequently found in velocity measurements of absorption lines in long period variables is probably the result of a shock of moderate amplitude located in or near the reversing layer and that the frequently observed correlation of velocity with excitation and ionization are a result of the velocity gradients produced by this shock in the atmosphere. A simple interpretation of the signs of the coefficients of the regression analysis is presented in terms of preshock, post shock, or across the shock, together with criteria for evaluating the validity of the fit. The amplitude of the reversing layer shock is estimated from an analysis of a series of plates for four long period variable stars along with the most probable stellar velocity for these stars.

Farsi version of the multidimensional health locus of control and God locus of health control scales: validity and reliability study among Iranian women with a family history of breast cancer.

PubMed

Hashemian, Masoumeh; Aminshokravi, Farkhonde; Hidarnia, Alireza; Lamyian, Minoor; Hassanpour, Kazem; Akaberi, Arash; Moshki, Mahdi

2014-09-01

To determine the Persian version's reliability and validity of the Multidimensional Health Locus of Control and God Health Locus of Control scales among women with family history of breast cancer. The cross-sectional study was conducted in Sabzevar, Iran, in 2012. It randomly selected women with family members affected by breast cancer. Predesigned questionnaires were completed through interviews. Content and face validity was evaluated using the opinions of a panel of experts, and construct validity was confirmed by applying confirmatory factor analysis.The instruments' reliability was assessed using Cronbach's alpha and test-retest reliability. There were 200 women in the study with their age ranging between 18 and 69 years and revealed the following; root mean square error of approximation for Multidimensional Health Locus of Control Scale = 0.013, and God Locus of Health Control Scale = 0.077; comparative fit index = 0.999, 0.998; incremental fit index = 0.999, 0.998;Tucker-Lewis fit index = 0.998, 0.998; and normed fit index = 0.983, 0.997 respectively. Cronbach's alpha was 0.61 for Internal Health Locus of Control, 0.8 for Chance Health Locus of Control, 0.68 for Power Health Locus of Control and 0.9 for God Locus Health Control. The Persian version of the subscales supported the main version.

Designing Epigenome Editors: Considerations of Biochemical and Locus Specificities.

PubMed

Sen, Dilara; Keung, Albert J

2018-01-01

The advent of locus-specific protein recruitment technologies has enabled a new class of studies in chromatin biology. Epigenome editors enable biochemical modifications of chromatin at almost any specific endogenous locus. Their locus specificity unlocks unique information including the functional roles of distinct modifications at specific genomic loci. Given the growing interest in using these tools for biological and translational studies, there are many specific design considerations depending on the scientific question or clinical need. Here we present and discuss important design considerations and challenges regarding the biochemical and locus specificities of epigenome editors. These include how to account for the complex biochemical diversity of chromatin; control for potential interdependency of epigenome editors and their resultant modifications; avoid sequestration effects; quantify the locus specificity of epigenome editors; and improve locus specificity by considering concentration, affinity, avidity, and sequestration effects.

The Resolved Stellar Populations Early Release Science Program

NASA Astrophysics Data System (ADS)

Gilbert, Karoline; Weisz, Daniel; Resolved Stellar Populations ERS Program Team

2018-06-01

The Resolved Stellar Populations Early Release Science Program (PI D. Weisz) will observe Local Group targets covering a range of stellar density and star formation histories, including a globular cluster, and ultra-faint dwarf galaxy, and a star-forming dwarf galaxy. Using observations of these diverse targets we will explore a broad science program: we will measure star formation histories, the sub-solar stellar initial mass function, and proper motions, perform studies of evolved stars, and map extinction in the target fields. Our observations will be of high archival value for other science such as calibrating stellar evolution models, studying variable stars, and searching for metal-poor stars. We will determine optimal observational setups and develop data reduction techniques that will be common to JWST studies of resolved stellar populations. We will also design, test, and release point spread function (PSF) fitting software specific to NIRCam and NIRISS, required for the crowded stellar regime. Prior to the Cycle 2 Call for Proposals, we will release PSF fitting software, matched HST and JWST catalogs, and clear documentation and step-by-step tutorials (such as Jupyter notebooks) for reducing crowded stellar field data and producing resolved stellar photometry catalogs, as well as for specific resolved stellar photometry science applications.

Activation of Extracellular Signal-Regulated Kinases (ERK 1/2) in the Locus Coeruleus Contributes to Pain-Related Anxiety in Arthritic Male Rats

PubMed Central

Borges, Gisela; Miguelez, Cristina; Neto, Fani; Mico, Juan Antonio; Ugedo, Luisa

2017-01-01

Abstract Background: There is increasing evidence suggesting that the Locus Coeruleus plays a role in pain-related anxiety. Indeed, we previously found that prolonged arthritis produces anxiety-like behavior in rats, along with enhanced expression of phosphorylated extracellular signal-regulated kinase 1/2 (a marker of plasticity) in the Locus Coeruleus. However, it is unknown how this effect correlates with the electrophysiological activity of Locus Coeruleus neurons or pain-related anxiety. Methods: Using the complete Freund’s adjuvant model of monoarthritis in male Sprague-Dawley rats, we studied the behavioral attributes of pain and anxiety as well as Locus Coeruleus electrophysiology in vivo 1 (MA1W) and 4 weeks (MA4W) after disease induction. Results: The manifestation of anxiety in MA4W was accompanied by dampened tonic Locus Coeruleus activity, which was coupled to an exacerbated evoked Locus Coeruleus response to noxious stimulation of the inflamed and healthy paw. When a mitogen-activating extracellular kinase inhibitor was administered to the contralateral Locus Coeruleus of MA4W, the phosphorylated extracellular signal-regulated kinase 1/2 levels in the Locus Coeruleus were restored and the exaggerated evoked response was blocked, reversing the anxiogenic-like behavior while pain hypersensitivity remained unaltered. Conclusion: As phosphorylated extracellular signal-regulated kinase 1/2 blockade in the Locus Coeruleus relieved anxiety and counteracted altered LC function, we propose that phosphorylated extracellular signal-regulated kinase 1/2 activation in the Locus Coeruleus plays a crucial role in pain-related anxiety. PMID:28158734

Activation of Extracellular Signal-Regulated Kinases (ERK 1/2) in the Locus Coeruleus Contributes to Pain-Related Anxiety in Arthritic Male Rats.

PubMed

Borges, Gisela; Miguelez, Cristina; Neto, Fani; Mico, Juan Antonio; Ugedo, Luisa; Berrocoso, Esther

2017-06-01

There is increasing evidence suggesting that the Locus Coeruleus plays a role in pain-related anxiety. Indeed, we previously found that prolonged arthritis produces anxiety-like behavior in rats, along with enhanced expression of phosphorylated extracellular signal-regulated kinase 1/2 (a marker of plasticity) in the Locus Coeruleus. However, it is unknown how this effect correlates with the electrophysiological activity of Locus Coeruleus neurons or pain-related anxiety. Using the complete Freund's adjuvant model of monoarthritis in male Sprague-Dawley rats, we studied the behavioral attributes of pain and anxiety as well as Locus Coeruleus electrophysiology in vivo 1 (MA1W) and 4 weeks (MA4W) after disease induction. The manifestation of anxiety in MA4W was accompanied by dampened tonic Locus Coeruleus activity, which was coupled to an exacerbated evoked Locus Coeruleus response to noxious stimulation of the inflamed and healthy paw. When a mitogen-activating extracellular kinase inhibitor was administered to the contralateral Locus Coeruleus of MA4W, the phosphorylated extracellular signal-regulated kinase 1/2 levels in the Locus Coeruleus were restored and the exaggerated evoked response was blocked, reversing the anxiogenic-like behavior while pain hypersensitivity remained unaltered. As phosphorylated extracellular signal-regulated kinase 1/2 blockade in the Locus Coeruleus relieved anxiety and counteracted altered LC function, we propose that phosphorylated extracellular signal-regulated kinase 1/2 activation in the Locus Coeruleus plays a crucial role in pain-related anxiety. © The Author 2017. Published by Oxford University Press on behalf of CINP.

The Anemic Stellar Halo of M101

NASA Astrophysics Data System (ADS)

Holwerda, Benne

2014-10-01

Models of galaxy formation in a cosmological context predict that massive disk galaxies should have richly-structured extended stellar halos, containing ~10% of a galaxy's stars, originating in large part from the tidal disruption of dwarf galaxies. Observations of a number of nearby disk galaxies have generally agreed with these expectations. Recent new observations in integrated light with a novel array of low scattered-light telephoto lenses have failed to convincingly detect a stellar halo in the nearby massive face-on disk galaxy M101 (van Dokkum et al. 2014). They argue that any halo has to have <0.3% of the mass of the galaxy. This halo would be the least massive of any massive disk galaxy in the local Universe (by factors of several) -- such a halo is not predicted or naturally interpreted by the models, and would present a critical challenge to the picture of ubiquitous stellar halos formed from the debris of disrupting dwarf galaxies.We propose to resolve the stellar populations of this uniquely anemic stellar halo for 6 orbits with HST (ACS and WFC3), allowing us to reach surface brightness limits sufficient to clearly detect and characterize M101's stellar halo if it carries more than 0.1% of M101's mass. With resolved stellar populations, we can use the gradient of stellar populations as a function of radius to separate stellar halo from disk, which is impossible using integrated light observations. The resolved stellar populations will reveal the halo mass to much greater accuracy, measure the halo radial profile, constrain any halo lopsidedness, estimate the halo's stellar metallicity, and permit an analysis of outer disk stellar populations.

Factor Specific Differences in Locus of Control for Emotionally Disturbed and Normal Children

ERIC Educational Resources Information Center

Kendall, Philip C.; And Others

1976-01-01

Institutionalized emotionally disturbed boys and noninstitutionalized normal boys were administered the Nowicki-Strickland Locus of Control Scale for Children. Locus of control and separate factor scores were calculated. Helplessness factor scores, but not overall locus of control scores, differentiated the two groups. (BJG)

Parental Locus of Control and the Assessment of Children's Personality Characteristics.

ERIC Educational Resources Information Center

Ollendick, Duane G.

1979-01-01

A study of fourth graders and their parents was conducted to determine the relationship between parents' locus of control and their children's locus of control, anxiety, intelligence, achievement, and behavioral adjustment. The relationship between mothers' locus of control and children's characteristics was more consistent than between fathers…

Factors associated with quitting areca (betel) quid chewing.

PubMed

Lai, Ching-Shiun; Shieh, Tien-Yu; Yang, Yi-Hsin Connie; Chong, Mian-Yoon; Hung, Hsin-Chia; Tsai, Chi-Cheng

2006-12-01

The purpose of this study was to provide useful data for a future abstinence project by identifying the factors related to quitting areca (betel) quid chewing. The study was cross-sectional. Data on demographic variables, psychological factors and substance-use behaviors were collected via questionnaires from 326 participants. Multiple logistic regression analysis indicated that the areca/betel quid chewers who were less educated (OR = 0.58, 95% CI = 0.34-0.98) were least likely to try to give up. Among the chewers who tried to quit, those employed as full-time drivers (OR = 2.24, 95% CI = 1.14-4.39), who had drinking habits (OR = 2.41, 95% CI = 1.24-4.66), and who preferred to chew only betel quid wrapped with leaf (OR = 4.44, 95% CI = 1.99-9.90) were more likely to fail. Chewers who successfully quit had a higher internal health locus of control compared with those who failed to quit (one-point increments, OR = 0.94, 95% CI = 0.90-0.98). The results suggest that health educators and researchers can better influence people's chewing behavior if the importance of chewers' education level, job type, substance use (i.e. drinking habits, type of betel quid), and level of health locus of control are all taken into consideration when devising interventions.

[Predictors of return to work after occupational injury in a locomotive enterprise].

PubMed

Hu, Jia; He, Yong-hua; Peng, Hua; Liang, You-xin

2010-06-01

To identify the potential determinants of return to work (RTW) following work-related injury. A historical cohort of workers with occupational injury in a state-owned locomotive vehicle company in central China was followed up for RTW. Demographic, employment and medical information was retrieved from the company archival documents; and post-injury information was interviewed by questionnaires. Univariate analysis and Cox Regression Model were used to examine the associations between potential determinants and outcomes of RTW. Three hundred of the 323 included cases (92.9%) eventually returned to work after the median absence of 43 days (average of 49.2 days). Factors from socio-demographic, clinical, economic and psychological domains were found affecting RTW in the univariate analyses. The multivariate analysis indicated that age, injury severity, injury locus, injury nature, pain in the injury locus, self-reported health status and pre-injury monthly salary were significant determinants of RTW. There are multidimensional factors affecting RTW after occupational injury. Proper clinical treatment and rehabilitation, as well as economic and social support to facilitate workers' RTW would be the priorities for intervention. Future studies should be conducted in a larger representative sample to confirm the findings and to develop a multidisciplinary intervention strategy towards promoting RTW.

Statistical correction of the Winner’s Curse explains replication variability in quantitative trait genome-wide association studies

PubMed Central

Pe’er, Itsik

2017-01-01

Genome-wide association studies (GWAS) have identified hundreds of SNPs responsible for variation in human quantitative traits. However, genome-wide-significant associations often fail to replicate across independent cohorts, in apparent inconsistency with their apparent strong effects in discovery cohorts. This limited success of replication raises pervasive questions about the utility of the GWAS field. We identify all 332 studies of quantitative traits from the NHGRI-EBI GWAS Database with attempted replication. We find that the majority of studies provide insufficient data to evaluate replication rates. The remaining papers replicate significantly worse than expected (p < 10−14), even when adjusting for regression-to-the-mean of effect size between discovery- and replication-cohorts termed the Winner’s Curse (p < 10−16). We show this is due in part to misreporting replication cohort-size as a maximum number, rather than per-locus one. In 39 studies accurately reporting per-locus cohort-size for attempted replication of 707 loci in samples with similar ancestry, replication rate matched expectation (predicted 458, observed 457, p = 0.94). In contrast, ancestry differences between replication and discovery (13 studies, 385 loci) cause the most highly-powered decile of loci to replicate worse than expected, due to difference in linkage disequilibrium. PMID:28715421

rs11613352 polymorphism (TT genotype) associates with a decrease of triglycerides and an increase of HDL in familial hypercholesterolemia patients.

PubMed

Aledo, Rosa; Padró, Teresa; Mata, Pedro; Alonso, Rodrigo; Badimon, Lina

2015-04-01

Recent genome-wide association studies have identified a locus on chromosome 12q13.3 associated with plasma levels of triglyceride and high-density lipoprotein cholesterol, with rs11613352 being the lead single nucleotide polymorphism in this genome-wide association study locus. The aim of the study is to investigate the involvement of rs11613352 in a population with high cardiovascular risk due to familial hypercholesterolemia. The single nucleotide polymorphism was genotyped by Taqman(®) assay in a cohort of 601 unrelated familial hypercholesterolemia patients and its association with plasma triglyceride and high-density lipoprotein cholesterol levels was analyzed by multivariate methods based on linear regression. Minimal allele frequency was 0.17 and genotype frequencies were 0.69, 0.27, and 0.04 for CC, CT, and TT genotypes, respectively. The polymorphism is associated in a recessive manner (TT genotype) with a decrease in triglyceride levels (P=.002) and with an increase in high-density lipoprotein cholesterol levels (P=.021) after adjusting by age and sex. The polymorphism rs11613352 may contribute to modulate the cardiovascular risk by modifying plasma lipid levels in familial hypercholesterolemia patients. Copyright © 2014 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

sunstardb: A Database for the Study of Stellar Magnetism and the Solar-stellar Connection

NASA Astrophysics Data System (ADS)

Egeland, Ricky

2018-05-01

The “solar-stellar connection” began as a relatively small field of research focused on understanding the processes that generate magnetic fields in stars and sometimes lead to a cyclic pattern of long-term variability in activity, as demonstrated by our Sun. This area of study has recently become more broadly pertinent to questions of exoplanet habitability and exo-space weather, as well as stellar evolution. In contrast to other areas of stellar research, individual stars in the solar-stellar connection often have a distinct identity and character in the literature, due primarily to the rarity of the decades-long time-series that are necessary for studying stellar activity cycles. Furthermore, the underlying stellar dynamo is not well understood theoretically, and is thought to be sensitive to several stellar properties, e.g., luminosity, differential rotation, and the depth of the convection zone, which in turn are often parameterized by other more readily available properties. Relevant observations are scattered throughout the literature and existing stellar databases, and consolidating information for new studies is a tedious and laborious exercise. To accelerate research in this area I developed sunstardb, a relational database of stellar properties and magnetic activity proxy time-series keyed by individual named stars. The organization of the data eliminates the need for the problematic catalog cross-matching operations inherent when building an analysis data set from heterogeneous sources. In this article I describe the principles behind sunstardb, the data structures and programming interfaces, as well as use cases from solar-stellar connection research.

Interaction effects on galaxy pairs with Gemini/GMOS- III: stellar population synthesis

NASA Astrophysics Data System (ADS)

Krabbe, A. C.; Rosa, D. A.; Pastoriza, M. G.; Hägele, G. F.; Cardaci, M. V.; Dors, O. L., Jr.; Winge, C.

2017-05-01

We present an observational study of the impacts of interactions on the stellar population in a sample of galaxy pairs. Long-slit spectra in the wavelength range 3440-7300 Å obtained with the Gemini Multi-Object Spectrograph (GMOS) at Gemini South for 15 galaxies in nine close pairs were used. The spatial distributions of the stellar population contributions were obtained using the stellar population synthesis code starlight. Taking into account the different contributions to the emitted light, we found that most of the galaxies in our sample are dominated by young/intermediate stellar populations. This result differs from the one derived for isolated galaxies, where the old stellar population dominates the disc surface brightness. We interpreted such different behaviour as being due to the effect of gas inflows along the discs of interacting galaxies on the star formation over a time-scale of the order of about 2 Gyr. We also found that, in general, the secondary galaxy of a pair has a higher contribution from the young stellar population than the primary one. We compared the estimated values of stellar and nebular extinction derived from the synthesis method and the Hα/Hβ emission-line ratio, finding that nebular extinctions are systematically higher than stellar ones by about a factor of 2. We did not find any correlation between nebular and stellar metallicities. Neither did we find a correlation between stellar metallicities and ages, while a positive correlation between nebular metallicities and stellar ages was obtained, with older regions being the most metal-rich.

Stellar activity and coronal heating: an overview of recent results

PubMed Central

Testa, Paola; Saar, Steven H.; Drake, Jeremy J.

2015-01-01

Observations of the coronae of the Sun and of solar-like stars provide complementary information to advance our understanding of stellar magnetic activity, and of the processes leading to the heating of their outer atmospheres. While solar observations allow us to study the corona at high spatial and temporal resolution, the study of stellar coronae allows us to probe stellar activity over a wide range of ages and stellar parameters. Stellar studies therefore provide us with additional tools for understanding coronal heating processes, as well as the long-term evolution of solar X-ray activity. We discuss how recent studies of stellar magnetic fields and coronae contribute to our understanding of the phenomenon of activity and coronal heating in late-type stars. PMID:25897087

LocusExplorer: a user-friendly tool for integrated visualization of human genetic association data and biological annotations.

PubMed

Dadaev, Tokhir; Leongamornlert, Daniel A; Saunders, Edward J; Eeles, Rosalind; Kote-Jarai, Zsofia

2016-03-15

: In this article, we present LocusExplorer, a data visualization and exploration tool for genetic association data. LocusExplorer is written in R using the Shiny library, providing access to powerful R-based functions through a simple user interface. LocusExplorer allows users to simultaneously display genetic, statistical and biological data for humans in a single image and allows dynamic zooming and customization of the plot features. Publication quality plots may then be produced in a variety of file formats. LocusExplorer is open source and runs through R and a web browser. It is available at www.oncogenetics.icr.ac.uk/LocusExplorer/ or can be installed locally and the source code accessed from https://github.com/oncogenetics/LocusExplorer tokhir.dadaev@icr.ac.uk. © The Author 2015. Published by Oxford University Press.

Self-regulated learning and achievement by middle-school children.

PubMed

Sink, C A; Barnett, J E; Hixon, J E

1991-12-01

The relationship of self-regulated learning to the achievement test scores of 62 Grade 6 students was studied. Generally, the metacognitive and affective variables correlated significantly with teachers' grades and standardized test scores in mathematics, reading, and science. Planning and self-assessment significantly predicted the six measures of achievement. Step-wise multiple regression analyses using the metacognitive and affective variables largely indicate that students' and teachers' perceptions of scholastic ability and planning appear to be the most salient factors in predicting academic performance. The locus of control dimension had no utility in predicting classroom grades and performance on standardized measures of achievement. The implications of the findings for teaching and learning are discussed.

Recent advances in non-LTE stellar atmosphere models

NASA Astrophysics Data System (ADS)

Sander, Andreas A. C.

2017-11-01

In the last decades, stellar atmosphere models have become a key tool in understanding massive stars. Applied for spectroscopic analysis, these models provide quantitative information on stellar wind properties as well as fundamental stellar parameters. The intricate non-LTE conditions in stellar winds dictate the development of adequate sophisticated model atmosphere codes. The increase in both, the computational power and our understanding of physical processes in stellar atmospheres, led to an increasing complexity in the models. As a result, codes emerged that can tackle a wide range of stellar and wind parameters. After a brief address of the fundamentals of stellar atmosphere modeling, the current stage of clumped and line-blanketed model atmospheres will be discussed. Finally, the path for the next generation of stellar atmosphere models will be outlined. Apart from discussing multi-dimensional approaches, I will emphasize on the coupling of hydrodynamics with a sophisticated treatment of the radiative transfer. This next generation of models will be able to predict wind parameters from first principles, which could open new doors for our understanding of the various facets of massive star physics, evolution, and death.

Star-disc interaction in galactic nuclei: formation of a central stellar disc

NASA Astrophysics Data System (ADS)

Panamarev, Taras; Shukirgaliyev, Bekdaulet; Meiron, Yohai; Berczik, Peter; Just, Andreas; Spurzem, Rainer; Omarov, Chingis; Vilkoviskij, Emmanuil

2018-05-01

We perform high-resolution direct N-body simulations to study the effect of an accretion disc on stellar dynamics in an active galactic nucleus (AGN). We show that the interaction of the nuclear stellar cluster (NSC) with the gaseous accretion disc (AD) leads to formation of a stellar disc in the central part of the NSC. The accretion of stars from the stellar disc on to the super-massive black hole is balanced by the capture of stars from the NSC into the stellar disc, yielding a stationary density profile. We derive the migration time through the AD to be 3 per cent of the half-mass relaxation time of the NSC. The mass and size of the stellar disc are 0.7 per cent of the mass and 5 per cent of the influence radius of the super-massive black hole. An AD lifetime shorter than the migration time would result in a less massive nuclear stellar disc. The detection of such a stellar disc could point to past activity of the hosting galactic nucleus.

Adolescent Values Clarification: A Positive Influence on Perceived Locus of Control.

ERIC Educational Resources Information Center

James, Mark R.

1990-01-01

Used locus of control assessments to monitor specific aspect of adolescent chemical dependency treatment program. Used song lyric analysis activities to note short-term modifications in experimental group's (N=10) perceived locus of control. No improvements were noted in matched control group's locus of control. Findings suggest that addictions…

Self-Esteem, Locus of Control, and Student Achievement.

ERIC Educational Resources Information Center

Sterbin, Allan; Rakow, Ernest

The direct effects of locus of control and self-esteem on standardized test scores were studied. The relationships among the standardized test scores and measures of locus of control and self-esteem for 12,260 students from the National Education Longitudinal Study 1994 database were examined, using the same definition of locus of control and…

Locus ceruleus neurons in people with autism contain no histochemically-detectable mercury.

PubMed

Pamphlett, Roger; Kum Jew, Stephen

2016-02-01

Exposure to environmental mercury has been proposed to play a part in autism. Mercury is selectively taken up by the human locus ceruleus, a region of the brain that has been implicated in autism. We therefore looked for the presence of mercury in the locus ceruleus of people who had autism, using the histochemical technique of autometallography which can detect nanogram amounts of mercury in tissues. In addition, we sought evidence of damage to locus ceruleus neurons in autism by immunostaining for hyperphosphorylated tau. No mercury was found in any neurons of the locus ceruleus of 6 individuals with autism (5 male, 1 female, age range 16-48 years). Mercury was present in locus ceruleus neurons in 7 of 11 (64%) age-matched control individuals who did not have autism, which is significantly more than in individuals with autism. No increase in numbers of locus ceruleus neurons containing hyperphosphorylated tau was detected in people with autism. In conclusion, most people with autism have not been exposed early in life to quantities of mercury large enough to be found later in adult locus ceruleus neurons. Human locus ceruleus neurons are sensitive indicators of mercury exposure, and mercury appears to remain in these neurons indefinitely, so these findings do not support the hypothesis that mercury neurotoxicity plays a role in autism.

Comparison of taxon-specific versus general locus sets for targeted sequence capture in plant phylogenomics.

PubMed

Chau, John H; Rahfeldt, Wolfgang A; Olmstead, Richard G

2018-03-01

Targeted sequence capture can be used to efficiently gather sequence data for large numbers of loci, such as single-copy nuclear loci. Most published studies in plants have used taxon-specific locus sets developed individually for a clade using multiple genomic and transcriptomic resources. General locus sets can also be developed from loci that have been identified as single-copy and have orthologs in large clades of plants. We identify and compare a taxon-specific locus set and three general locus sets (conserved ortholog set [COSII], shared single-copy nuclear [APVO SSC] genes, and pentatricopeptide repeat [PPR] genes) for targeted sequence capture in Buddleja (Scrophulariaceae) and outgroups. We evaluate their performance in terms of assembly success, sequence variability, and resolution and support of inferred phylogenetic trees. The taxon-specific locus set had the most target loci. Assembly success was high for all locus sets in Buddleja samples. For outgroups, general locus sets had greater assembly success. Taxon-specific and PPR loci had the highest average variability. The taxon-specific data set produced the best-supported tree, but all data sets showed improved resolution over previous non-sequence capture data sets. General locus sets can be a useful source of sequence capture targets, especially if multiple genomic resources are not available for a taxon.

External locus of control contributes to racial disparities in memory and reasoning training gains in ACTIVE

PubMed Central

Zahodne, Laura B.; Meyer, Oanh L.; Choi, Eunhee; Thomas, Michael L.; Willis, Sherry L.; Marsiske, Michael; Gross, Alden L.; Rebok, George W.; Parisi, Jeanine M.

2015-01-01

Racial disparities in cognitive outcomes may be partly explained by differences in locus of control. African Americans report more external locus of control than non-Hispanic Whites, and external locus of control is associated with poorer health and cognition. The aims of this study were to compare cognitive training gains between African American and non-Hispanic White participants in the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study and determine whether racial differences in training gains are mediated by locus of control. The sample comprised 2,062 (26% African American) adults aged 65 and older who participated in memory, reasoning, or speed training. Latent growth curve models evaluated predictors of 10-year cognitive trajectories separately by training group. Multiple group modeling examined associations between training gains and locus of control across racial groups. Compared to non-Hispanic Whites, African Americans evidenced less improvement in memory and reasoning performance after training. These effects were partially mediated by locus of control, controlling for age, sex, education, health, depression, testing site, and initial cognitive ability. African Americans reported more external locus of control, which was associated with smaller training gains. External locus of control also had a stronger negative association with reasoning training gain for African Americans than for Whites. No racial difference in training gain was identified for speed training. Future intervention research with African Americans should test whether explicitly targeting external locus of control leads to greater cognitive improvement following cognitive training. PMID:26237116

High-density genetic maps for loci involved in nuclear male sterility (NMS1) and sporophytic self-incompatibility (S-locus) in chicory (Cichorium intybus L., Asteraceae).

PubMed

Gonthier, Lucy; Blassiau, Christelle; Mörchen, Monika; Cadalen, Thierry; Poiret, Matthieu; Hendriks, Theo; Quillet, Marie-Christine

2013-08-01

High-density genetic maps were constructed for loci involved in nuclear male sterility (NMS1-locus) and sporophytic self-incompatibility (S-locus) in chicory (Cichorium intybus L.). The mapping population consisted of 389 F1' individuals derived from a cross between two plants, K28 (male-sterile) and K59 (pollen-fertile), both heterozygous at the S-locus. This F1' mapping population segregated for both male sterility (MS) and strong self-incompatibility (SI) phenotypes. Phenotyping F1' individuals for MS allowed us to map the NMS1-locus to linkage group (LG) 5, while controlled diallel and factorial crosses to identify compatible/incompatible phenotypes mapped the S-locus to LG2. To increase the density of markers around these loci, bulked segregant analysis was used. Bulks and parental plants K28 and K59 were screened using amplified fragment length polymorphism (AFLP) analysis, with a complete set of 256 primer combinations of EcoRI-ANN and MseI-CNN. A total of 31,000 fragments were generated, of which 2,350 showed polymorphism between K59 and K28. Thirteen AFLP markers were identified close to the NMS1-locus and six in the vicinity of the S-locus. From these AFLP markers, eight were transformed into sequence-characterized amplified region (SCAR) markers and of these five showed co-dominant polymorphism. The chromosomal regions containing the NMS1-locus and the S-locus were each confined to a region of 0.8 cM. In addition, we mapped genes encoding proteins similar to S-receptor kinase, the female determinant of sporophytic SI in the Brasicaceae, and also markers in the vicinity of the putative S-locus of sunflower, but none of these genes or markers mapped close to the chicory S-locus.

On the Scatter of the Present-day Stellar Metallicity–Mass Relation of Cluster Dwarf Galaxies

NASA Astrophysics Data System (ADS)

Engler, Christoph; Lisker, Thorsten; Pillepich, Annalisa

2018-04-01

We examine the scatter of the relation between stellar mass and stellar metallicity for cluster dwarf galaxies in the cosmological simulation Illustris. The mass-metallicity relation exhibits the smallest intrinsic scatter at the galaxies' times of peak stellar mass, suggesting stellar mass stripping to be the primary effect responsible for the rather broad relation at present. However, for about 40% of galaxies in the high-metallicity tail of the relation, we find mass stripping to coincide with an increased enrichment of stellar metallicity, possibly caused by the stripping of low-metallicity stars in the galaxy outskirts.

Estimation of distances to stars with stellar parameters from LAMOST

DOE PAGES

Carlin, Jeffrey L.; Liu, Chao; Newberg, Heidi Jo; ...

2015-06-05

Here, we present a method to estimate distances to stars with spectroscopically derived stellar parameters. The technique is a Bayesian approach with likelihood estimated via comparison of measured parameters to a grid of stellar isochrones, and returns a posterior probability density function for each star's absolute magnitude. We tailor this technique specifically to data from the Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST) survey. Because LAMOST obtains roughly 3000 stellar spectra simultaneously within each ~5-degree diameter "plate" that is observed, we can use the stellar parameters of the observed stars to account for the stellar luminosity function and targetmore » selection effects. This removes biasing assumptions about the underlying populations, both due to predictions of the luminosity function from stellar evolution modeling, and from Galactic models of stellar populations along each line of sight. Using calibration data of stars with known distances and stellar parameters, we show that our method recovers distances for most stars within ~20%, but with some systematic overestimation of distances to halo giants. We apply our code to the LAMOST database, and show that the current precision of LAMOST stellar parameters permits measurements of distances with ~40% error bars. This precision should improve as the LAMOST data pipelines continue to be refined.« less

Estimation of distances to stars with stellar parameters from LAMOST

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carlin, Jeffrey L.; Liu, Chao; Newberg, Heidi Jo

Here, we present a method to estimate distances to stars with spectroscopically derived stellar parameters. The technique is a Bayesian approach with likelihood estimated via comparison of measured parameters to a grid of stellar isochrones, and returns a posterior probability density function for each star's absolute magnitude. We tailor this technique specifically to data from the Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST) survey. Because LAMOST obtains roughly 3000 stellar spectra simultaneously within each ~5-degree diameter "plate" that is observed, we can use the stellar parameters of the observed stars to account for the stellar luminosity function and targetmore » selection effects. This removes biasing assumptions about the underlying populations, both due to predictions of the luminosity function from stellar evolution modeling, and from Galactic models of stellar populations along each line of sight. Using calibration data of stars with known distances and stellar parameters, we show that our method recovers distances for most stars within ~20%, but with some systematic overestimation of distances to halo giants. We apply our code to the LAMOST database, and show that the current precision of LAMOST stellar parameters permits measurements of distances with ~40% error bars. This precision should improve as the LAMOST data pipelines continue to be refined.« less

The difference in age of the two counter-rotating stellar disks of the spiral galaxy NGC 4138

NASA Astrophysics Data System (ADS)

Pizzella, A.; Morelli, L.; Corsini, E. M.; Dalla Bontà, E.; Coccato, L.; Sanjana, G.

2014-10-01

Context. Galaxies accrete material from the environment through acquisitions and mergers. These processes contribute to the galaxy assembly and leave their fingerprints on the galactic morphology, internal kinematics of gas and stars, and stellar populations. Aims: The Sa spiral NGC 4138 is known to host two counter-rotating stellar disks, with the ionized gas co-rotating with one of them. We measured the kinematics and properties of the two counter-rotating stellar populations to constrain their formation scenario. Methods: A spectroscopic decomposition of the observed major-axis spectrum was performed to disentangle the relative contribution of the two counter-rotating stellar and one ionized-gas components. The line-strength indices of the two counter-rotating stellar components were measured and modeled with single stellar population models that account for the α/Fe overabundance. Results: The counter-rotating stellar population is younger, marginally more metal poor, and more α-enhanced than the main stellar component. The younger stellar component is also associated with a star-forming ring. Conclusions: The different properties of the counter-rotating stellar components of NGC 4138 rule out the idea that they formed because of bar dissolution. Our findings support the results of numerical simulations in which the counter-rotating component assembled from gas accreted on retrograde orbits from the environment or from the retrograde merging with a gas-rich dwarf galaxy. Based on observation carried out at the Galileo 1.22 m telescope at Padua University.

Arousal and Expression of Anger: A Function of Locus of Control?

ERIC Educational Resources Information Center

Stockin, Bruce C.

Although psychologists have been investigating locus of control for more than two decades, few studies have examined how locus of control interacts with affective variables. To investigate the function of locus of control on arousal patterns and expressions of anger, 120 college students (60 internals, 60 externals, as measured by Rotter's (1966)…

The Impact of Locus of Control on Language Achievement

ERIC Educational Resources Information Center

Nodoushan, Mohammad Ali Salmani

2012-01-01

This study hypothesized that students' loci of control affected their language achievement. 198 (N = 198) EFL students took the Rotter's (1966) locus of control test and were classified as locus-internal (ni = 78), and locus-external (ne = 120). They then took their ordinary courses and at the end of the semester, they were given their exams.…

Reframing Student Affairs Leadership: An Analysis of Organizational Frames of Reference and Locus of Control

ERIC Educational Resources Information Center

Tull, Ashley; Freeman, Jerrid P.

2011-01-01

Examined in this study were the identified frames of reference and locus of control used by 478 student affairs administrators. Administrator responses were examined to identify frames of reference most commonly used and their preference order. Locus of control most commonly used and the relationship between frames of reference and locus of…

Locus of Control and Achievement of At-Risk Adolescent Black Males.

ERIC Educational Resources Information Center

Howerton, D. Lynn; And Others

The relationship between locus of control and academic achievement was studied for 42 adolescent black males identified as at-risk by their teachers. The Nowicki-Strickland Locus of Control scale (NS-LOC) for children was used as a measure of locus of control. School grade average and the Stanford Achievement Test (SFAT) battery composite provided…

On the Relation of Locus of Control and L2 Reading and Writing Achievement

ERIC Educational Resources Information Center

Ghonsooly, Behzad; Shirvan, Majid Elahi

2011-01-01

Locus of control, a psychological construct, has been the focus of attention in recent decades. Psychologists have discussed the effect of locus of control on achieving life goals in social/psychological interactions. While learning a foreign language involves both social interactions and psychological processes, the role and relation of locus of…

Diverse stellar haloes in nearby Milky Way mass disc galaxies

NASA Astrophysics Data System (ADS)

Harmsen, Benjamin; Monachesi, Antonela; Bell, Eric F.; de Jong, Roelof S.; Bailin, Jeremy; Radburn-Smith, David J.; Holwerda, Benne W.

2017-04-01

We have examined the resolved stellar populations at large galactocentric distances along the minor axis (from 10 kpc up to between 40 and 75 kpc), with limited major axis coverage, of six nearby highly inclined Milky Way (MW) mass disc galaxies using Hubble Space Telescope data from the Galaxy haloes, Outer discs, Substructure, Thick discs, and Star clusters (GHOSTS) survey. We select red giant branch stars to derive stellar halo density profiles. The projected minor axis density profiles can be approximated by power laws with projected slopes of -2 to -3.7 and a diversity of stellar halo masses of 1-6 × 109 M⊙, or 2-14 per cent of the total galaxy stellar masses. The typical intrinsic scatter around a smooth power-law fit is 0.05-0.1 dex owing to substructure. By comparing the minor and major axis profiles, we infer projected axis ratios c/a at ˜25 kpc between 0.4and0.75. The GHOSTS stellar haloes are diverse, lying between the extremes charted out by the (rather atypical) haloes of the MW and M31. We find a strong correlation between the stellar halo metallicities and the stellar halo masses. We compare our results with cosmological models, finding good agreement between our observations and accretion-only models where the stellar haloes are formed by the disruption of dwarf satellites. In particular, the strong observed correlation between stellar halo metallicity and mass is naturally reproduced. Low-resolution hydrodynamical models have unrealistically high stellar halo masses. Current high-resolution hydrodynamical models appear to predict stellar halo masses somewhat higher than observed but with reasonable metallicities, metallicity gradients, and density profiles.

Life in the Outer Limits: Insight into Hierarchical Merging from the Outermost Structure of the Andromeda Stellar Halo

NASA Astrophysics Data System (ADS)

Beaton, Rachael; Majewski, S. R.; Patterson, R. J.; Guhathakurta, P.; Gilbert, K.; Kalirai, J. S.; Tollerud, E. J.; SPLASH Team

2014-01-01

Owing to their large dynamical timescales, the stellar haloes of Milky Way (MW) sized galaxies represent ideal environments to test modern theories of galaxy formation in the Lambda-CDM paradigm. Only in stellar haloes can the remnants of hierarchical accretion be preserved over long timescales as in-tact dwarf satellites or as tidal debris and can be easily distinguished from the underlying smooth structure. Stellar haloes, however, remain some of the most difficult galactic structures to constrain due to their large angular extent and extremely low surface brightness. Thus, the basic properties of stellar haloes -- the overall stellar distribution, substructure fraction, global kinematics and detailed stellar content -- remained relatively unconstrained. In this thesis, we present several projects designed to understand the current structure and the the formation of the Andromeda (M31) stellar halo, the only stellar halo -- besides our own -- that is within reach of current ground based facilities on the large scale required to constrain the basic properties of stellar haloes. First, we describe a seven season imaging campaign comprising the backbone of the Spectroscopic and Photometric Landscape of the Andromeda Stellar Halo (SPLASH) program. This survey is unique in its application of the Washington + DDO51 filter system to select individual M31 RGB stars without spectroscopic follow up. Second, we use the SPLASH photometric survey to identify sample of halo stars at projected radii of 120 kpc, for which we have obtained spectroscopic follow-up. Third, we add this large radius sample to the existing spectroscopic results from SPLASH, and use this unique sample to explore the stellar kinematics of the halo at large radii with full azimuthal coverage. Lastly, we preview on-going work to constrain the formation of the Andromeda stellar halo, using both in-tact satellites and resolved M31 halo members as tracers of its accretion history.

Unresolved versus resolved: testing the validity of young simple stellar population models with VLT/MUSE observations of NGC 3603

NASA Astrophysics Data System (ADS)

Kuncarayakti, H.; Galbany, L.; Anderson, J. P.; Krühler, T.; Hamuy, M.

2016-09-01

Context. Stellar populations are the building blocks of galaxies, including the Milky Way. The majority, if not all, extragalactic studies are entangled with the use of stellar population models given the unresolved nature of their observation. Extragalactic systems contain multiple stellar populations with complex star formation histories. However, studies of these systems are mainly based upon the principles of simple stellar populations (SSP). Hence, it is critical to examine the validity of SSP models. Aims: This work aims to empirically test the validity of SSP models. This is done by comparing SSP models against observations of spatially resolved young stellar population in the determination of its physical properties, that is, age and metallicity. Methods: Integral field spectroscopy of a young stellar cluster in the Milky Way, NGC 3603, was used to study the properties of the cluster as both a resolved and unresolved stellar population. The unresolved stellar population was analysed using the Hα equivalent width as an age indicator and the ratio of strong emission lines to infer metallicity. In addition, spectral energy distribution (SED) fitting using STARLIGHT was used to infer these properties from the integrated spectrum. Independently, the resolved stellar population was analysed using the colour-magnitude diagram (CMD) to determine age and metallicity. As the SSP model represents the unresolved stellar population, the derived age and metallicity were tested to determine whether they agree with those derived from resolved stars. Results: The age and metallicity estimate of NGC 3603 derived from integrated spectroscopy are confirmed to be within the range of those derived from the CMD of the resolved stellar population, including other estimates found in the literature. The result from this pilot study supports the reliability of SSP models for studying unresolved young stellar populations. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programme 60.A-9344.

Color-size Relations of Disc Galaxies with Similar Stellar Masses

NASA Astrophysics Data System (ADS)

Fu, W.; Chang, R. X.; Shen, S. Y.; Zhang, B.

2011-01-01

To investigate the correlations between colors and sizes of disc galaxies with similar stellar masses, a sample of 7959 local face-on disc galaxies is collected from the main galaxy sample of the Seventh Data Release of Sloan Digital Sky Survey (SDSS DR7). Our results show that, under the condition that the stellar masses of disc galaxies are similar, the relation between u-r and size is weak, while g-r, r-i and r-z colors decrease with disk size. This means that the color-size relations of disc galaxies with similar stellar masses do exist, i.e., the more extended disc galaxies with similar stellar masses tend to have bluer colors. An artificial sample is constructed to confirm that this correlation is not driven by the color-stellar mass relations and size-stellar mass relation of disc galaxies. Our results suggest that the mass distribution of disk galaxies may have an important influence on their stellar formation history, i.e., the galaxies with more extended mass distribution evolve more slowly.

Solar astrophysics - Ghettosis from, or symbiosis with, stellar and galactic astrophysics

NASA Technical Reports Server (NTRS)

Pecker, J.-C.; Thomas, R. N.

1976-01-01

The purpose of the paper is to show how the solar-stellar symbiotic approach has led to the modeling of a star as a concentration of matter and energy. By 'solar-stellar symbiosis' is meant the philosophy of investigation according to which one asks what change in our general understanding of stellar structure and of stellar spectroscopic diagnostics is required to satisfy both the sun and an unusual star when, for example, some feature of an unusual star is discovered. The evolution of stellar models is traced, from walled, thermodynamic-equilibrium models to de-isolated models featuring transition zones and nonlocal thermodynamic equilibrium.

The stellar metallicity gradients in galaxy discs in a cosmological scenario

NASA Astrophysics Data System (ADS)

Tissera, Patricia B.; Machado, Rubens E. G.; Sanchez-Blazquez, Patricia; Pedrosa, Susana E.; Sánchez, Sebastián F.; Snaith, Owain; Vilchez, Jose

2016-08-01

Context. The stellar metallicity gradients of disc galaxies provide information on disc assembly, star formation processes, and chemical evolution. They also might store information on dynamical processes that could affect the distribution of chemical elements in the gas phase and the stellar components. Understanding their joint effects within a hierarchical clustering scenario is of paramount importance. Aims: We studied the stellar metallicity gradients of simulated discs in a cosmological simulation. We explored the dependence of the stellar metallicity gradients on stellar age and on the size and mass of the stellar discs. Methods: We used a catalogue of galaxies with disc components selected from a cosmological hydrodynamical simulation performed including a physically motivated supernova feedback and chemical evolution. Disc components were defined based on angular momentum and binding energy criteria. The metallicity profiles were estimated for stars with different ages. We confront our numerical findings with results from the Calar Alto Legacy Integral Field Area (CALIFA) Survey. Results: The simulated stellar discs are found to have metallicity profiles with slopes in global agreement with observations. Low stellar mass galaxies tend to have a larger variety of metallicity slopes. When normalized by the half-mass radius, the stellar metallicity gradients do not show any dependence and the dispersion increases significantly, regardless of the galaxy mass. Galaxies with stellar masses o f around 1010M⊙ show steeper negative metallicity gradients. The stellar metallicity gradients correlate with the half-mass radius. However, the correlation signal is not present when they are normalized by the half-mass radius. Stellar discs with positive age gradients are detected to have negative and positive metallicity gradients, depending on the relative importance of recent star formation activity in the central regions. Conclusions: Our results suggest that inside-out formation is the main process responsible for the metallicity and age profiles. The large dispersions in the metallicity gradients as a function of stellar mass could be ascribed to the effects of dynamical processes such as mergers, interactions and/or migration as well as those regulating the conversion of gas into stars. The fingerprints of the inside-out formation seem better preserved by the stellar metallicity gradients as a function of the half-mass radius.

External locus of control contributes to racial disparities in memory and reasoning training gains in ACTIVE.

PubMed

Zahodne, Laura B; Meyer, Oanh L; Choi, Eunhee; Thomas, Michael L; Willis, Sherry L; Marsiske, Michael; Gross, Alden L; Rebok, George W; Parisi, Jeanine M

2015-09-01

Racial disparities in cognitive outcomes may be partly explained by differences in locus of control. African Americans report more external locus of control than non-Hispanic Whites, and external locus of control is associated with poorer health and cognition. The aims of this study were to compare cognitive training gains between African American and non-Hispanic White participants in the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study and determine whether racial differences in training gains are mediated by locus of control. The sample comprised 2,062 (26% African American) adults aged 65 and older who participated in memory, reasoning, or speed training. Latent growth curve models evaluated predictors of 10-year cognitive trajectories separately by training group. Multiple group modeling examined associations between training gains and locus of control across racial groups. Compared to non-Hispanic Whites, African Americans evidenced less improvement in memory and reasoning performance after training. These effects were partially mediated by locus of control, controlling for age, sex, education, health, depression, testing site, and initial cognitive ability. African Americans reported more external locus of control, which was associated with smaller training gains. External locus of control also had a stronger negative association with reasoning training gain for African Americans than for Whites. No racial difference in training gain was identified for speed training. Future intervention research with African Americans should test whether explicitly targeting external locus of control leads to greater cognitive improvement following cognitive training. (c) 2015 APA, all rights reserved).

Evaluation of two multi-locus sequence typing schemes for commensal Escherichia coli from dairy cattle in Washington State.

PubMed

Ahmed, Sara; Besser, Thomas E; Call, Douglas R; Weissman, Scott J; Jones, Lisa P; Davis, Margaret A

2016-05-01

Multi-locus sequence typing (MLST) is a useful system for phylogenetic and epidemiological studies of multidrug-resistant Escherichiacoli. Most studies utilize a seven-locus MLST, but an alternate two-locus typing method (fumC and fimH; CH typing) has been proposed that may offer a similar degree of discrimination at lower cost. Herein, we compare CH typing to the standard seven-locus method for typing commensal E. coli isolates from dairy cattle. In addition, we evaluated alternative combinations of eight loci to identify combinations that maximize discrimination and congruence with standard seven-locus MLST among commensal E. coli while minimizing the cost. We also compared both methods when used for typing uropathogenic E. coli (UPEC). CH typing was less discriminatory for commensal E. coli than the standard seven-locus method (Simpson's Index of Diversity=0.933 [0.902-0.964] and 0.97 [0.96-0.979], respectively). Combining fimH with housekeeping gene loci improved discriminatory power for commensal E. coli from cattle but resulted in poor congruence with MLST. We found that a four-locus typing method including the housekeeping genes adk, purA, gyrB and recA could be used to minimize cost without sacrificing discriminatory power or congruence with Achtman seven-locus MLST when typing commensal E. coli. Copyright © 2016 Elsevier B.V. All rights reserved.

Rasch Analysis of the Locus-of-Hope Scale. Brief Report

ERIC Educational Resources Information Center

Gadiana, Leny G.; David, Adonis P.

2015-01-01

The Locus-of-Hope Scale (LHS) was developed as a measure of the locus-of-hope dimensions (Bernardo, 2010). The present study adds to the emerging literature on locus-of-hope by assessing the psychometric properties of the LHS using Rasch analysis. The results from the Rasch analyses of the four subscales of LHS provided evidence on the…

A Study of Reward Preference in Taiwanese Gifted and Nongifted Students with Differential Locus of Control

ERIC Educational Resources Information Center

Wu, Su Chen; Elliott, Robert T.

2008-01-01

The purpose of the study was to investigate whether gifted and nongifted students' preferences for different types of reward were affected by differential locus of control. In total, 181 gifted and 107 nongifted junior high school students in Taiwan participated. The Nowicki-Strickland Locus of Control Scale was used as a measure of locus of…

Internal health locus of control predicts willingness to track health behaviors online and with smartphone applications.

PubMed

Bennett, Brooke L; Goldstein, Carly M; Gathright, Emily C; Hughes, Joel W; Latner, Janet D

2017-12-01

Given rising technology use across all demographic groups, digital interventions offer a potential strategy for increasing access to health information and care. Research is lacking on identifying individual differences that impact willingness to use digital interventions, which may affect patient engagement. Health locus of control, the amount of control an individual believes they have over their own health, may predict willingness to use mobile health (mHealth) applications ('apps') and online trackers. A cross-sectional study (n = 276) was conducted to assess college students' health locus of control beliefs and willingness to use health apps and online trackers. Internal and powerful other health locus of control beliefs predicted willingness to use health apps and online trackers while chance health locus of control beliefs did not. Individuals with internal and powerful other health locus of control beliefs are more willing than those with chance health locus of control beliefs to utilize a form of technology to monitor or change health behaviors. Health locus of control is an easy-to-assess patient characteristic providers can measure to identify which patients are more likely to utilize mHealth apps and online trackers.

A relation between the characteristic stellar ages of galaxies and their intrinsic shapes

NASA Astrophysics Data System (ADS)

van de Sande, Jesse; Scott, Nicholas; Bland-Hawthorn, Joss; Brough, Sarah; Bryant, Julia J.; Colless, Matthew; Cortese, Luca; Croom, Scott M.; d'Eugenio, Francesco; Foster, Caroline; Goodwin, Michael; Konstantopoulos, Iraklis S.; Lawrence, Jon S.; McDermid, Richard M.; Medling, Anne M.; Owers, Matt S.; Richards, Samuel N.; Sharp, Rob

2018-06-01

Stellar population and stellar kinematic studies provide unique but complementary insights into how galaxies build-up their stellar mass and angular momentum1-3. A galaxy's mean stellar age reveals when stars were formed, but provides little constraint on how the galaxy's mass was assembled. Resolved stellar dynamics4 trace the change in angular momentum due to mergers, but major mergers tend to obscure the effect of earlier interactions5. With the rise of large multi-object integral field spectroscopic surveys, such as SAMI6 and MaNGA7, and single-object integral field spectroscopic surveys (for example, ATLAS3D (ref. 8), CALIFA9, MASSIVE10), it is now feasible to connect a galaxy's star formation and merger history on the same resolved physical scales, over a large range in galaxy mass, morphology and environment4,11,12. Using the SAMI Galaxy Survey, here we present a combined study of spatially resolved stellar kinematics and global stellar populations. We find a strong correlation of stellar population age with location in the (V/σ, ɛe) diagram that links the ratio of ordered rotation to random motions in a galaxy to its observed ellipticity. For the large majority of galaxies that are oblate rotating spheroids, we find that characteristic stellar age follows the intrinsic ellipticity of galaxies remarkably well.

Evolution of the Stellar Mass–Metallicity Relation. I. Galaxies in the z ∼ 0.4 Cluster Cl0024

NASA Astrophysics Data System (ADS)

Leethochawalit, Nicha; Kirby, Evan N.; Moran, Sean M.; Ellis, Richard S.; Treu, Tommaso

2018-03-01

We present the stellar mass–stellar metallicity relationship (MZR) in the galaxy cluster Cl0024+1654 at z ∼ 0.4 using full-spectrum stellar population synthesis modeling of individual quiescent galaxies. The lower limit of our stellar mass range is M * = 109.7 M ⊙, the lowest galaxy mass at which individual stellar metallicity has been measured beyond the local universe. We report a detection of an evolution of the stellar MZR with observed redshift at 0.037 ± 0.007 dex per Gyr, consistent with the predictions from hydrodynamical simulations. Additionally, we find that the evolution of the stellar MZR with observed redshift can be explained by an evolution of the stellar MZR with the formation time of galaxies, i.e., when the single stellar population (SSP)-equivalent ages of galaxies are taken into account. This behavior is consistent with stars forming out of gas that also has an MZR with a normalization that decreases with redshift. Lastly, we find that over the observed mass range, the MZR can be described by a linear function with a shallow slope ([{Fe}/{{H}}]\\propto (0.16+/- 0.03){log}{M}* ). The slope suggests that galaxy feedback, in terms of mass-loading factor, might be mass-independent over the observed mass and redshift range.

A relation between the characteristic stellar ages of galaxies and their intrinsic shapes

NASA Astrophysics Data System (ADS)

van de Sande, Jesse; Scott, Nicholas; Bland-Hawthorn, Joss; Brough, Sarah; Bryant, Julia J.; Colless, Matthew; Cortese, Luca; Croom, Scott M.; d'Eugenio, Francesco; Foster, Caroline; Goodwin, Michael; Konstantopoulos, Iraklis S.; Lawrence, Jon S.; McDermid, Richard M.; Medling, Anne M.; Owers, Matt S.; Richards, Samuel N.; Sharp, Rob

2018-04-01

Stellar population and stellar kinematic studies provide unique but complementary insights into how galaxies build-up their stellar mass and angular momentum1-3. A galaxy's mean stellar age reveals when stars were formed, but provides little constraint on how the galaxy's mass was assembled. Resolved stellar dynamics4 trace the change in angular momentum due to mergers, but major mergers tend to obscure the effect of earlier interactions5. With the rise of large multi-object integral field spectroscopic surveys, such as SAMI6 and MaNGA7, and single-object integral field spectroscopic surveys (for example, ATLAS3D (ref. 8), CALIFA9, MASSIVE10), it is now feasible to connect a galaxy's star formation and merger history on the same resolved physical scales, over a large range in galaxy mass, morphology and environment4,11,12. Using the SAMI Galaxy Survey, here we present a combined study of spatially resolved stellar kinematics and global stellar populations. We find a strong correlation of stellar population age with location in the (V/σ, ɛe) diagram that links the ratio of ordered rotation to random motions in a galaxy to its observed ellipticity. For the large majority of galaxies that are oblate rotating spheroids, we find that characteristic stellar age follows the intrinsic ellipticity of galaxies remarkably well.

The stability of locus equation slopes across stop consonant voicing/aspiration

NASA Astrophysics Data System (ADS)

Sussman, Harvey M.; Modarresi, Golnaz

2004-05-01

The consistency of locus equation slopes as phonetic descriptors of stop place in CV sequences across voiced and voiceless aspirated stops was explored in the speech of five male speakers of American English and two male speakers of Persian. Using traditional locus equation measurement sites for F2 onsets, voiceless labial and coronal stops had significantly lower locus equation slopes relative to their voiced counterparts, whereas velars failed to show voicing differences. When locus equations were derived using F2 onsets for voiced stops that were measured closer to the stop release burst, comparable to the protocol for measuring voiceless aspirated stops, no significant effects of voicing/aspiration on locus equation slopes were observed. This methodological factor, rather than an underlying phonetic-based explanation, provides a reasonable account for the observed flatter locus equation slopes of voiceless labial and coronal stops relative to voiced cognates reported in previous studies [Molis et al., J. Acoust. Soc. Am. 95, 2925 (1994); O. Engstrand and B. Lindblom, PHONUM 4, 101-104]. [Work supported by NIH.

The C allele of JAK2 rs4495487 is an additional candidate locus that contributes to myeloproliferative neoplasm predisposition in the Japanese population

PubMed Central

2012-01-01

Background Polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF) are myeloproliferative neoplasms (MPNs) characterized in most cases by a unique somatic mutation, JAK2 V617F. Recent studies revealed that JAK2 V617F occurs more frequently in a specific JAK2 haplotype, named JAK2 46/1 or GGCC haplotype, which is tagged by rs10974944 (C/G) and/or rs12343867 (T/C). This study examined the impact of single nucleotide polymorphisms (SNPs) of the JAK2 locus on MPNs in a Japanese population. Methods We sequenced 24 JAK2 SNPs in Japanese patients with PV. We then genotyped 138 MPN patients (33 PV, 96 ET, and 9 PMF) with known JAK2 mutational status and 107 controls for a novel SNP, in addition to two SNPs known to be part of the 46/1 haplotype (rs10974944 and rs12343867). Associations with risk of MPN were estimated by odds ratios and their 95% confidence intervals using logistic regression. Results A novel locus, rs4495487 (T/C), with a mutated T allele was significantly associated with PV. Similar to rs10974944 and rs12343867, rs4495487 in the JAK2 locus is significantly associated with JAK2-positive MPN. Based on the results of SNP analysis of the three JAK2 locus, we defined the "GCC genotype" as having at least one minor allele in each SNP (G allele in rs10974944, C allele in rs4495487, and C allele in rs12343867). The GCC genotype was associated with increased risk of both JAK2 V617F-positive and JAK2 V617F-negative MPN. In ET patients, leukocyte count and hemoglobin were significantly associated with JAK2 V617F, rather than the GCC genotype. In contrast, none of the JAK2 V617F-negative ET patients without the GCC genotype had thrombosis, and splenomegaly was frequently seen in this subset of ET patients. PV patients without the GCC genotype were significantly associated with high platelet count. Conclusions Our results indicate that the C allele of JAK2 rs4495487, in addition to the 46/1 haplotype, contributes significantly to the occurrence of JAK2 V617F-positive and JAK2 V617F-negative MPNs in the Japanese population. Because lack of the GCC genotype represents a distinct clinical-hematological subset of MPN, analyzing JAK2 SNPs and quantifying JAK2 V617F mutations will provide further insights into the molecular pathogenesis of MPN. PMID:22251709

A novel variational Bayes multiple locus Z-statistic for genome-wide association studies with Bayesian model averaging

PubMed Central

Logsdon, Benjamin A.; Carty, Cara L.; Reiner, Alexander P.; Dai, James Y.; Kooperberg, Charles

2012-01-01

Motivation: For many complex traits, including height, the majority of variants identified by genome-wide association studies (GWAS) have small effects, leaving a significant proportion of the heritable variation unexplained. Although many penalized multiple regression methodologies have been proposed to increase the power to detect associations for complex genetic architectures, they generally lack mechanisms for false-positive control and diagnostics for model over-fitting. Our methodology is the first penalized multiple regression approach that explicitly controls Type I error rates and provide model over-fitting diagnostics through a novel normally distributed statistic defined for every marker within the GWAS, based on results from a variational Bayes spike regression algorithm. Results: We compare the performance of our method to the lasso and single marker analysis on simulated data and demonstrate that our approach has superior performance in terms of power and Type I error control. In addition, using the Women's Health Initiative (WHI) SNP Health Association Resource (SHARe) GWAS of African-Americans, we show that our method has power to detect additional novel associations with body height. These findings replicate by reaching a stringent cutoff of marginal association in a larger cohort. Availability: An R-package, including an implementation of our variational Bayes spike regression (vBsr) algorithm, is available at http://kooperberg.fhcrc.org/soft.html. Contact: blogsdon@fhcrc.org Supplementary information: Supplementary data are available at Bioinformatics online. PMID:22563072

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reines, Amy E.; Volonteri, Marta, E-mail: reines@umich.edu

Scaling relations between central black hole (BH) mass and host galaxy properties are of fundamental importance to studies of BH and galaxy evolution throughout cosmic time. Here we investigate the relationship between BH mass and host galaxy total stellar mass using a sample of 262 broad-line active galactic nuclei (AGNs) in the nearby universe (z < 0.055), as well as 79 galaxies with dynamical BH masses. The vast majority of our AGN sample is constructed using Sloan Digital Sky Survey spectroscopy and searching for Seyfert-like narrow-line ratios and broad Hα emission. BH masses are estimated using standard virial techniques. Wemore » also include a small number of dwarf galaxies with total stellar masses M{sub stellar} ≲ 10{sup 9.5} M{sub ⊙} and a subsample of the reverberation-mapped AGNs. Total stellar masses of all 341 galaxies are calculated in the most consistent manner feasible using color-dependent mass-to-light ratios. We find a clear correlation between BH mass and total stellar mass for the AGN host galaxies, with M{sub BH} ∝ M{sub stellar}, similar to that of early-type galaxies with dynamically detected BHs. However, the relation defined by the AGNs has a normalization that is lower by more than an order of magnitude, with a BH-to-total stellar mass fraction of M{sub BH}/M{sub stellar} ∼ 0.025% across the stellar mass range 10{sup 8} ≤ M{sub stellar}/M{sub ⊙} ≤ 10{sup 12}. This result has significant implications for studies at high redshift and cosmological simulations in which stellar bulges cannot be resolved.« less

Compact Starburst Galaxies with Fast Outflows: Spatially Resolved Stellar Mass Profiles

NASA Astrophysics Data System (ADS)

Gottlieb, Sophia; Diamond-Stanic, Aleksandar; Lipscomb, Charles; Ohene, Senyo; Rines, Josh; Moustakas, John; Sell, Paul; Tremonti, Christy; Coil, Alison; Rudnick, Gregory; Hickox, Ryan C.; Geach, James; Kepley, Amanda

2018-01-01

Powerful galactic winds driven by stellar feedback and black hole accretion are thought to play an important role in regulating star formation in galaxies. In particular, strong stellar feedback from supernovae, stellar winds, radiation pressure, and cosmic rays is required by simulations of star-forming galaxies to prevent the vast majority of baryons from cooling and collapsing to form stars. However, it remains unclear whether these stellar processes play a significant role in expelling gas and shutting down star formation in massive progenitors of quiescent galaxies. What are the limits of stellar feedback? We present multi-band photometry with HST/WFC3 (F475W, F814W, F160W) for a dozen compact starburst galaxies at z~0.6 with half-light radii that suggest incredibly large central escape velocities. These massive galaxies are driving fast (>1000 km/s) outflows that have been previously attributed to stellar feedback associated with the compact (r~100 pc) starburst. But how compact is the stellar mass? In the context of the stellar feedback hypothesis, it is unclear whether these fast outflows are being driven at velocities comparable to the escape velocity of an incredibly dense stellar system (as predicted by some models of radiation-pressure winds) or at velocities that exceed the central escape velocity by large factor. Our spatially resolved measurements with HST show that the stellar mass is more extended than the light, and this requires that the physical mechanism responsible for driving the winds must be able to launch gas at velocities that are factors of 5-10 beyond the central escape velocity.

Cooperative Genome-Wide Analysis Shows Increased Homozygosity in Early Onset Parkinson's Disease

PubMed Central

Nalls, Michael A.; Martinez, Maria; Schulte, Claudia; Holmans, Peter; Gasser, Thomas; Hardy, John; Singleton, Andrew B.; Wood, Nicholas W.; Brice, Alexis; Heutink, Peter; Williams, Nigel; Morris, Huw R.

2012-01-01

Parkinson's disease (PD) occurs in both familial and sporadic forms, and both monogenic and complex genetic factors have been identified. Early onset PD (EOPD) is particularly associated with autosomal recessive (AR) mutations, and three genes, PARK2, PARK7 and PINK1, have been found to carry mutations leading to AR disease. Since mutations in these genes account for less than 10% of EOPD patients, we hypothesized that further recessive genetic factors are involved in this disorder, which may appear in extended runs of homozygosity. We carried out genome wide SNP genotyping to look for extended runs of homozygosity (ROHs) in 1,445 EOPD cases and 6,987 controls. Logistic regression analyses showed an increased level of genomic homozygosity in EOPD cases compared to controls. These differences are larger for ROH of 9 Mb and above, where there is a more than three-fold increase in the proportion of cases carrying a ROH. These differences are not explained by occult recessive mutations at existing loci. Controlling for genome wide homozygosity in logistic regression analyses increased the differences between cases and controls, indicating that in EOPD cases ROHs do not simply relate to genome wide measures of inbreeding. Homozygosity at a locus on chromosome19p13.3 was identified as being more common in EOPD cases as compared to controls. Sequencing analysis of genes and predicted transcripts within this locus failed to identify a novel mutation causing EOPD in our cohort. There is an increased rate of genome wide homozygosity in EOPD, as measured by an increase in ROHs. These ROHs are a signature of inbreeding and do not necessarily harbour disease-causing genetic variants. Although there might be other regions of interest apart from chromosome 19p13.3, we lack the power to detect them with this analysis. PMID:22427796

Segregation analysis of prostate cancer in France: evidence for autosomal dominant inheritance and residual brother-brother dependence.

PubMed

Valeri, A; Briollais, L; Azzouzi, R; Fournier, G; Mangin, P; Berthon, P; Cussenot, O; Demenais, F

2003-03-01

Four segregation analyses concerning prostate cancer (CaP), three conducted in the United States and one in Northern Europe, have shown evidence for a dominant major gene but with different parameter estimates. A recent segregation analysis of Australian pedigrees has found a better fit of a two-locus model than single-locus models. This model included a dominantly inherited increased risk that was greater at younger ages and a recessively inherited or X-linked increased risk that was greater at older ages. Recent linkage analyses have led to the detection of at least 8 CaP predisposing genes, suggesting a complex inheritance and genetic heterogeneity. To assess the nature of familial aggregation of prostate cancer in France, segregation analysis was conducted in 691 families ascertained through 691 CaP patients, recruited from three French hospitals and unselected with respect to age at diagnosis, clinical stage or family history. This mode of family inclusion, without any particular selection of the probands, is unique, as probands from all previous analyses were selected according to various criteria. Segregation analysis was carried out using the logistic hazard regressive model, as incorporated in the REGRESS program, which can accommodate a major gene effect, residual familial dependences of any origin (genetic and/or environmental), and covariates, while including survival analysis concepts. Segregation analysis showed evidence for the segregation of an autosomal dominant gene (allele frequency of 0.03%) with an additional brother-brother dependence. The estimated cumulative risks of prostate cancer by age 85 years, among subjects with the at-risk genotype, were 86% in the fathers' generation and 99% in the probands' generation. This study supports the model of Mendelian transmission of a rare autosomal dominant gene with high penetrance, and demonstrates that additional genetic and/or common sibling environmental factors are involved to account for the familial clustering of CaP.

Targeted Optimization of Quasi-Symmetric Stellarators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hegna, Chris C.; Anderson, D. T.; Talmadge, J. N.

2016-10-06

The proposed research focuses on targeted areas of plasma physics dedicated to improving the stellarator concept. Research was pursued in the technical areas of edge/divertor physics in 3D configurations, magnetic island physics in stellarators, the role of 3D shaping on microinstabilities and turbulent transport and energetic ion confinement in stellarators.

Trans-ancestral studies fine map the SLE-susceptibility locus TNFSF4.

PubMed

Manku, Harinder; Langefeld, Carl D; Guerra, Sandra G; Malik, Talat H; Alarcon-Riquelme, Marta; Anaya, Juan-Manuel; Bae, Sang-Cheol; Boackle, Susan A; Brown, Elizabeth E; Criswell, Lindsey A; Freedman, Barry I; Gaffney, Patrick M; Gregersen, Peter A; Guthridge, Joel M; Han, Sang-Hoon; Harley, John B; Jacob, Chaim O; James, Judith A; Kamen, Diane L; Kaufman, Kenneth M; Kelly, Jennifer A; Martin, Javier; Merrill, Joan T; Moser, Kathy L; Niewold, Timothy B; Park, So-Yeon; Pons-Estel, Bernardo A; Sawalha, Amr H; Scofield, R Hal; Shen, Nan; Stevens, Anne M; Sun, Celi; Gilkeson, Gary S; Edberg, Jeff C; Kimberly, Robert P; Nath, Swapan K; Tsao, Betty P; Vyse, Tim J

2013-01-01

We previously established an 80 kb haplotype upstream of TNFSF4 as a susceptibility locus in the autoimmune disease SLE. SLE-associated alleles at this locus are associated with inflammatory disorders, including atherosclerosis and ischaemic stroke. In Europeans, the TNFSF4 causal variants have remained elusive due to strong linkage disequilibrium exhibited by alleles spanning the region. Using a trans-ancestral approach to fine-map the locus, utilising 17,900 SLE and control subjects including Amerindian/Hispanics (1348 cases, 717 controls), African-Americans (AA) (1529, 2048) and better powered cohorts of Europeans and East Asians, we find strong association of risk alleles in all ethnicities; the AA association replicates in African-American Gullah (152,122). The best evidence of association comes from two adjacent markers: rs2205960-T (P=1.71 × 10(-34) , OR=1.43[1.26-1.60]) and rs1234317-T (P=1.16 × 10(-28) , OR=1.38[1.24-1.54]). Inference of fine-scale recombination rates for all populations tested finds the 80 kb risk and non-risk haplotypes in all except African-Americans. In this population the decay of recombination equates to an 11 kb risk haplotype, anchored in the 5' region proximal to TNFSF4 and tagged by rs2205960-T after 1000 Genomes phase 1 (v3) imputation. Conditional regression analyses delineate the 5' risk signal to rs2205960-T and the independent non-risk signal to rs1234314-C. Our case-only and SLE-control cohorts demonstrate robust association of rs2205960-T with autoantibody production. The rs2205960-T is predicted to form part of a decameric motif which binds NF-κBp65 with increased affinity compared to rs2205960-G. ChIP-seq data also indicate NF-κB interaction with the DNA sequence at this position in LCL cells. Our research suggests association of rs2205960-T with SLE across multiple groups and an independent non-risk signal at rs1234314-C. rs2205960-T is associated with autoantibody production and lymphopenia. Our data confirm a global signal at TNFSF4 and a role for the expressed product at multiple stages of lymphocyte dysregulation during SLE pathogenesis. We confirm the validity of trans-ancestral mapping in a complex trait.

Trans-Ancestral Studies Fine Map the SLE-Susceptibility Locus TNFSF4

PubMed Central

Manku, Harinder; Langefeld, Carl D.; Guerra, Sandra G.; Malik, Talat H.; Alarcon-Riquelme, Marta; Anaya, Juan-Manuel; Bae, Sang-Cheol; Boackle, Susan A.; Brown, Elizabeth E.; Criswell, Lindsey A.; Freedman, Barry I.; Gaffney, Patrick M.; Gregersen, Peter A.; Guthridge, Joel M.; Han, Sang-Hoon; Harley, John B.; Jacob, Chaim O.; James, Judith A.; Kamen, Diane L.; Kaufman, Kenneth M.; Kelly, Jennifer A.; Martin, Javier; Merrill, Joan T.; Moser, Kathy L.; Niewold, Timothy B.; Park, So-Yeon; Pons-Estel, Bernardo A.; Sawalha, Amr H.; Scofield, R. Hal; Shen, Nan; Stevens, Anne M.; Sun, Celi; Gilkeson, Gary S.; Edberg, Jeff C.; Kimberly, Robert P.; Nath, Swapan K.; Tsao, Betty P.; Vyse, Tim J.

2013-01-01

We previously established an 80 kb haplotype upstream of TNFSF4 as a susceptibility locus in the autoimmune disease SLE. SLE-associated alleles at this locus are associated with inflammatory disorders, including atherosclerosis and ischaemic stroke. In Europeans, the TNFSF4 causal variants have remained elusive due to strong linkage disequilibrium exhibited by alleles spanning the region. Using a trans-ancestral approach to fine-map the locus, utilising 17,900 SLE and control subjects including Amerindian/Hispanics (1348 cases, 717 controls), African-Americans (AA) (1529, 2048) and better powered cohorts of Europeans and East Asians, we find strong association of risk alleles in all ethnicities; the AA association replicates in African-American Gullah (152,122). The best evidence of association comes from two adjacent markers: rs2205960-T (P = 1.71×10−34, OR = 1.43[1.26–1.60]) and rs1234317-T (P = 1.16×10−28, OR = 1.38[1.24–1.54]). Inference of fine-scale recombination rates for all populations tested finds the 80 kb risk and non-risk haplotypes in all except African-Americans. In this population the decay of recombination equates to an 11 kb risk haplotype, anchored in the 5′ region proximal to TNFSF4 and tagged by rs2205960-T after 1000 Genomes phase 1 (v3) imputation. Conditional regression analyses delineate the 5′ risk signal to rs2205960-T and the independent non-risk signal to rs1234314-C. Our case-only and SLE-control cohorts demonstrate robust association of rs2205960-T with autoantibody production. The rs2205960-T is predicted to form part of a decameric motif which binds NF-κBp65 with increased affinity compared to rs2205960-G. ChIP-seq data also indicate NF-κB interaction with the DNA sequence at this position in LCL cells. Our research suggests association of rs2205960-T with SLE across multiple groups and an independent non-risk signal at rs1234314-C. rs2205960-T is associated with autoantibody production and lymphopenia. Our data confirm a global signal at TNFSF4 and a role for the expressed product at multiple stages of lymphocyte dysregulation during SLE pathogenesis. We confirm the validity of trans-ancestral mapping in a complex trait. PMID:23874208

The Ties that Bind (the Igh Locus).

PubMed

Krangel, Michael S

2016-05-01

Immunoglobulin heavy-chain locus V(D)J recombination requires a 3D chromatin organization which permits widely distributed variable (V) gene segments to contact distant diversity (D) and joining (J) gene segments. A recent study has identified key nodes in the locus interactome, paving the way for new molecular insights into how the locus is configured for recombination. Copyright © 2016 Elsevier Ltd. All rights reserved.

Quantitative trait locus mapping of human blood pressure to a genetic region at or near the lipoprotein lipase gene locus on chromosome 8p22.

PubMed Central

Wu, D A; Bu, X; Warden, C H; Shen, D D; Jeng, C Y; Sheu, W H; Fuh, M M; Katsuya, T; Dzau, V J; Reaven, G M; Lusis, A J; Rotter, J I; Chen, Y D

1996-01-01

Resistance to insulin-mediated glucose disposal is a common finding in patients with non-insulin-dependent diabetes mellitus (NIDDM), as well as in nondiabetic individuals with hypertension. In an effort to identify the generic loci responsible for variations in blood pressure in individuals at increased risk of insulin resistance, we studied the distribution of blood pressure in 48 Taiwanese families with NIDDM and conducted quantitative sib-pair linkage analysis with candidate loci for insulin resistance, lipid metabolism, and blood pressure control. We found no evidence for linkage of the angiotensin converting enzyme locus on chromosome 17, nor the angiotensinogen and renin loci on chromosome 1, with either systolic or diastolic blood pressures. In contrast, we obtained significant evidence for linkage or systolic blood pressure, but not diastolic blood pressure, to a genetic region at or near the lipoprotein lipase (LPL) locus on the short arm of chromosome 8 (P = 0.002, n = 125 sib-pairs, for the haplotype generated from two simple sequence repeat markers within the LPL gene). Further strengthening this linkage observation, two flanking marker loci for LPL locus, D8S261 (9 cM telomeric to LPL locus) and D8S282 (3 cM centromeric to LPL locus), also showed evidence for linkage with systolic blood pressure (P = 0.02 and 0.0002 for D8S261 and D8S282, respectively). Two additional centromeric markers (D8S133, 5 cM from LPL locus, and NEFL, 11 cM from LPL locus) yielded significant P values of 0.01 and 0.001, respectively. Allelic variation around the LPL gene locus accounted for as much as 52-73% of the total interindividual variation in systolic blood pressure levels in this data set. Thus, we have identified a genetic locus at or near the LPL gene locus which contributes to the variation of systolic blood pressure levels in nondiabetic family members at high risk for insulin resistance and NIDDM. PMID:8621801

Connecting Stellar Substructures to the Oscillating Disk: Monoceros and A13

NASA Astrophysics Data System (ADS)

Sheffield, Allyson; Tzanidakis, Anastasios; Johnston, Kathryn; Price-Whelan, Adrian

2018-01-01

Recent observations of stellar substructures in the Milky Way have challenged our view of where the traditional disk ends. By assessing the stellar populations in a stellar feature, particularly the fraction of RR Lyrae to M giant stars, an accretion scenario can be ruled out in favor of a kicked-out disk origin. A more definitive distinction can be made with the inclusion of high-resolution abundances. I will present evidence that two low latitude stellar substructures, the Monoceros Ring and A13, originated in the Galactic disk and were kicked out to their current location, in the outer regions of the stellar disk, due to a dynamic perturbation to the disk.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Torchia, B.S.; Call, L.M.; Migeon, B.R.

The relationship between the transcriptional state of a locus and the time when it replicates during DNA synthesis is increasingly apparent. Active autosomal genes tend to replicate early, whereas inactive ones are more permissive and frequently replicate later. Although the inactive X chromosome replicates later than its active homologue, little is known about the replication of X-linked genes. The authors have used FISH to examine the replication of loci on the active X chromosome that are not transcribed, either because the tissue analyzed was not the expressing tissue (F8C), because the locus is silent on all active X chromosomes (XIST),more » or because it has been mutated by expansion and methylation of a CpG island (FMR1). In this assay, an unreplicated locus is characterized by a single hybridization signal, and a replicated locus is characterized by a doublet hybridization signal. The percentage of doublets is used as a measure of relative time of replication in S phase. The results show that the FMR1 gene replicates relatively later in fragile X(fraX) males with the full mutation than in normal males, irrespective of the probe used. The F8C locus is late replicating in both normal and fraX males and replicates at nearly the same time on active and inactive X in females. The XIST locus replicates late in all the males studied and asynchronously in female cells. From the late replication of the locus on the active X in males, the authors deduce that the locus on the active X is the later replicating locus in female cells. They conclude that (1) the expansion of the FMR1 locus leads to late replication, (2) silence of the XIST gene in males is associated with late replication of the locus, and (3) this assay will be useful for further studies of the relationship between transcription and replication. 32 refs., 2 figs., 5 tabs.« less

METALLICITY AND AGE OF THE STELLAR STREAM AROUND THE DISK GALAXY NGC 5907

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laine, Seppo; Grillmair, Carl J.; Capak, Peter

2016-09-01

Stellar streams have become central to studies of the interaction histories of nearby galaxies. To characterize the most prominent parts of the stellar stream around the well-known nearby ( d  = 17 Mpc) edge-on disk galaxy NGC 5907, we have obtained and analyzed new, deep gri Subaru/Suprime-Cam and 3.6 μ m Spitzer /Infrared Array Camera observations. Combining the near-infrared 3.6 μ m data with visible-light images allows us to use a long wavelength baseline to estimate the metallicity and age of the stellar population along an ∼60 kpc long segment of the stream. We have fitted the stellar spectral energy distributionmore » with a single-burst stellar population synthesis model and we use it to distinguish between the proposed satellite accretion and minor/major merger formation models of the stellar stream around this galaxy. We conclude that a massive minor merger (stellar mass ratio of at least 1:8) can best account for the metallicity of −0.3 inferred along the brightest parts of the stream.« less

Know the Planet, Know the Star: Precise Stellar Parameters with Kepler

NASA Astrophysics Data System (ADS)

Sandford, Emily; Kipping, David M.

2017-01-01

The Kepler space telescope has revolutionized exoplanetary science with unprecedentedly precise photometric measurements of the light curves of transiting planets. In addition to information about the planet and its orbit, encoded in each Kepler transiting planet light curve are certain properties of the host star, including the stellar density and the limb darkening profile. For planets with strong prior constraints on orbital eccentricity (planets to which we refer as “stellar anchors”), we may measure these stellar properties directly from the light curve. This method promises to aid greatly in the characterization of transiting planet host stars targeted by the upcoming NASA TESS mission and any long-period, singly-transiting planets discovered in the same systems. Using Bayesian inference, we fit a transit model, including a nonlinear limb darkening law, to a large sample of transiting planet hosts to measure their stellar properties. We present the results of our analysis, including posterior stellar density distributions for each stellar host, and show how the method yields superior precision to literature stellar properties in the majority of cases studied.

Near-Field Cosmology with Resolved Stellar Populations Around Local Volume LMC Stellar-Mass Galaxies

NASA Astrophysics Data System (ADS)

Carlin, Jeffrey L.; Sand, David J.; Willman, Beth; Brodie, Jean P.; Crnojevic, Denija; Forbes, Duncan; Hargis, Jonathan R.; Peter, Annika; Pucha, Ragadeepika; Romanowsky, Aaron J.; Spekkens, Kristine; Strader, Jay

2018-06-01

We discuss our ongoing observational program to comprehensively map the entire virial volumes of roughly LMC stellar mass galaxies at distances of ~2-4 Mpc. The MADCASH (Magellanic Analog Dwarf Companions And Stellar Halos) survey will deliver the first census of the dwarf satellite populations and stellar halo properties within LMC-like environments in the Local Volume. Our results will inform our understanding of the recent DES discoveries of dwarf satellites tentatively affiliated with the LMC/SMC system. This program has already yielded the discovery of the faintest known dwarf galaxy satellite of an LMC stellar-mass host beyond the Local Group, based on deep Subaru+HyperSuprimeCam imaging reaching ~2 magnitudes below its TRGB, and at least two additional candidate satellites. We will summarize the survey results and status to date, highlighting some challenges encountered and lessons learned as we process the data for this program through a prototype LSST pipeline. Our program will examine whether LMC stellar mass dwarfs have extended stellar halos, allowing us to assess the relative contributions of in-situ stars vs. merger debris to their stellar populations and halo density profiles. We outline the constraints on galaxy formation models that will be provided by our observations of low-mass galaxy halos and their satellites.

Tidal effects on stellar activity

NASA Astrophysics Data System (ADS)

Poppenhaeger, K.

2017-10-01

The architecture of many exoplanetary systems is different from the solar system, with exoplanets being in close orbits around their host stars and having orbital periods of only a few days. We can expect interactions between the star and the exoplanet for such systems that are similar to the tidal interactions observed in close stellar binary systems. For the exoplanet, tidal interaction can lead to circularization of its orbit and the synchronization of its rotational and orbital period. For the host star, it has long been speculated if significant angular momentum transfer can take place between the planetary orbit and the stellar rotation. In the case of the Earth-Moon system, such tidal interaction has led to an increasing distance between Earth and Moon. For stars with Hot Jupiters, where the orbital period of the exoplanet is typically shorter than the stellar rotation period, one expects a decreasing semimajor axis for the planet and enhanced stellar rotation, leading to increased stellar activity. Also excess turbulence in the stellar convective zone due to rising and subsiding tidal bulges may change the magnetic activity we observe for the host star. I will review recent observational results on stellar activity and tidal interaction in the presence of close-in exoplanets, and discuss the effects of enhanced stellar activity on the exoplanets in such systems.

Locus of control and contraceptive knowledge, attitude and practice among university students.

PubMed

Alves, Aline Salheb; Lopes, Maria Helena Baena de Moraes

2010-02-01

To assess the relationship between locus of control and knowledge, attitude and practice regarding pill and condom use among university students. The inquiry was developed in Campinas, a city in Southeastern Brazil, in 2006. A total of 295 adolescent newcomers to a public university answered a structured questionnaire and Levenson's multidimensional locus of control scale. The scores of the dimensions of locus of control were calculated and Spearman's correlation coefficient was used to assess their correlation with knowledge and practice concerning pill and condom use. In order to assess the relationship between the dimensions of locus of control and sociodemographic variables and variables related to the individuals' sex life, Kruskal-Wallis and Mann-Whitney tests were used. Male adolescents had higher scores of powerful others externality when compared to female adolescents (p=0.01). Students living alone had lower internality (p=0.01). When locus of control was compared to condom use in the first intercourse, considering only the 102 students who informed the age of the beginning of sexual activity, greater internality was found among male adolescents who did not use condoms (p<0.05). When the locus of control scores were correlated with contraceptive knowledge and practice, it was found that the higher the powerful others externality locus, the lower the adequate use of contraceptive methods (r = -0.22, p=0.03). The powerful others externality locus influences the practice of contraceptive use in this group of adolescents.

A new stellar spectrum interpolation algorithm and its application to Yunnan-III evolutionary population synthesis models

NASA Astrophysics Data System (ADS)

Cheng, Liantao; Zhang, Fenghui; Kang, Xiaoyu; Wang, Lang

2018-05-01

In evolutionary population synthesis (EPS) models, we need to convert stellar evolutionary parameters into spectra via interpolation in a stellar spectral library. For theoretical stellar spectral libraries, the spectrum grid is homogeneous on the effective-temperature and gravity plane for a given metallicity. It is relatively easy to derive stellar spectra. For empirical stellar spectral libraries, stellar parameters are irregularly distributed and the interpolation algorithm is relatively complicated. In those EPS models that use empirical stellar spectral libraries, different algorithms are used and the codes are often not released. Moreover, these algorithms are often complicated. In this work, based on a radial basis function (RBF) network, we present a new spectrum interpolation algorithm and its code. Compared with the other interpolation algorithms that are used in EPS models, it can be easily understood and is highly efficient in terms of computation. The code is written in MATLAB scripts and can be used on any computer system. Using it, we can obtain the interpolated spectra from a library or a combination of libraries. We apply this algorithm to several stellar spectral libraries (such as MILES, ELODIE-3.1 and STELIB-3.2) and give the integrated spectral energy distributions (ISEDs) of stellar populations (with ages from 1 Myr to 14 Gyr) by combining them with Yunnan-III isochrones. Our results show that the differences caused by the adoption of different EPS model components are less than 0.2 dex. All data about the stellar population ISEDs in this work and the RBF spectrum interpolation code can be obtained by request from the first author or downloaded from http://www1.ynao.ac.cn/˜zhangfh.

Kinematic and stellar population properties of the counter-rotating components in the S0 galaxy NGC 1366

NASA Astrophysics Data System (ADS)

Morelli, L.; Pizzella, A.; Coccato, L.; Corsini, E. M.; Dalla Bontà, E.; Buson, L. M.; Ivanov, V. D.; Pagotto, I.; Pompei, E.; Rocco, M.

2017-04-01

Context. Many disk galaxies host two extended stellar components that rotate in opposite directions. The analysis of the stellar populations of the counter-rotating components provides constraints on the environmental and internal processes that drive their formation. Aims: The S0 NGC 1366 in the Fornax cluster is known to host a stellar component that is kinematically decoupled from the main body of the galaxy. Here we successfully separated the two counter-rotating stellar components to independently measure the kinematics and properties of their stellar populations. Methods: We performed a spectroscopic decomposition of the spectrum obtained along the galaxy major axis and separated the relative contribution of the two counter-rotating stellar components and of the ionized-gas component. We measured the line-strength indices of the two counter-rotating stellar components and modeled each of them with single stellar population models that account for the α/Fe overabundance. Results: We found that the counter-rotating stellar component is younger, has nearly the same metallicity, and is less α/Fe enhanced than the corotating component. Unlike most of the counter-rotating galaxies, the ionized gas detected in NGC 1366 is neither associated with the counter-rotating stellar component nor with the main galaxy body. On the contrary, it has a disordered distribution and a disturbed kinematics with multiple velocity components observed along the minor axis of the galaxy. Conclusions: The different properties of the counter-rotating stellar components and the kinematic peculiarities of the ionized gas suggest that NGC 1366 is at an intermediate stage of the acquisition process, building the counter-rotating components with some gas clouds still falling onto the galaxy. Based on observations made with ESO Telescopes at the La Silla-Paranal Observatory under programmes 075.B-0794 and 077.B-0767.

Absorption line indices in the UV. I. Empirical and theoretical stellar population models

NASA Astrophysics Data System (ADS)

Maraston, C.; Nieves Colmenárez, L.; Bender, R.; Thomas, D.

2009-01-01

Aims: Stellar absorption lines in the optical (e.g. the Lick system) have been extensively studied and constitute an important stellar population diagnostic for galaxies in the local universe and up to moderate redshifts. Proceeding towards higher look-back times, galaxies are younger and the ultraviolet becomes the relevant spectral region where the dominant stellar populations shine. A comprehensive study of ultraviolet absorption lines of stellar population models is however still lacking. With this in mind, we study absorption line indices in the far and mid-ultraviolet in order to determine age and metallicity indicators for UV-bright stellar populations in the local universe as well as at high redshift. Methods: We explore empirical and theoretical spectral libraries and use evolutionary population synthesis to compute synthetic line indices of stellar population models. From the empirical side, we exploit the IUE-low resolution library of stellar spectra and system of absorption lines, from which we derive analytical functions (fitting functions) describing the strength of stellar line indices as a function of gravity, temperature and metallicity. The fitting functions are entered into an evolutionary population synthesis code in order to compute the integrated line indices of stellar populations models. The same line indices are also directly evaluated on theoretical spectral energy distributions of stellar population models based on Kurucz high-resolution synthetic spectra, In order to select indices that can be used as age and/or metallicity indicators for distant galaxies and globular clusters, we compare the models to data of template globular clusters from the Magellanic Clouds with independently known ages and metallicities. Results: We provide synthetic line indices in the wavelength range ~1200 Å to ~3000 Å for stellar populations of various ages and metallicities.This adds several new indices to the already well-studied CIV and SiIV absorptions. Based on the comparison with globular cluster data, we select a set of 11 indices blueward of the 2000 Å rest-frame that allows us to recover well the ages and the metallicities of the clusters. These indices are ideal to study ages and metallicities of young galaxies at high redshift. We also provide the synthetic high-resolution stellar population SEDs.

On the Locus Formed by the Maximum Heights of Projectile Motion with Air Resistance

ERIC Educational Resources Information Center

Hernandez-Saldana, H.

2010-01-01

We present an analysis on the locus formed by the set of maxima of the trajectories of a projectile launched in a medium with linear drag. Such a place, the locus of apexes, is written in terms of the Lambert "W" function in polar coordinates, confirming the special role played by this function in the problem. To characterize the locus, a study of…

SE33 locus as a reliable genetic marker for forensic DNA analysis systems

PubMed

Bhinder, Munir Ahmad; Zahoor, Muhammad Yasir; Sadia, Haleema; Qasim, Muhammad; Perveen, Rukhsana; Anjum, Ghulam Murtaza; Iqbal, Muhammad; Ullah, Najeeb; Shehzad, Wasim; Tariq, Muhammad; Waryah, Ali Muhammad

2018-06-14

Background/aim: Genetic variation, an authentic tool of individual discrimination, is being used for forensic investigations worldwide. A missing result for even one out of 13-17 markers leads to an inconclusive report. Additional reliable markers are required to compensate such deficiencies. The SE33 locus has high genetic variability in different populations and is being used in forensic investigation systems in some countries. The purpose of the study was to assess the viability of use of the SE33 locus as a supportive marker for forensic DNA profiling. Materials and methods: Amplification of the SE33 locus was performed using the PowerPlex ES Monoplex System SE33 (Promega). After genotyping 204 Pakistani individuals, different genetic and forensic parameters for the SE33 locus were studied. Results: Genotyping of the SE33 locus revealed a total of 43 alleles including 3 novel alleles. Significant values of different forensic and genetic parameters including power of discrimination, power of exclusion, and polymorphism information content were observed. Conclusions: Addition of the SE33 locus in forensic DNA profiling may help to produce conclusive reports where results are inconclusive due to degraded evidence samples. The SE33 locus can confidently be used for Pakistani and neighboring populations having common ancestors from Iran to Central Asia, the Middle East, India and Turkey.

Prevalence of Porphyromonas gingivalis four rag locus genotypes in patients of orthodontic gingivitis and periodontitis.

PubMed

Liu, Yi; Zhang, Yujie; Wang, Lili; Guo, Yang; Xiao, Shuiqing

2013-01-01

Porphyromonas gingivalis is considered as a major etiological agent in periodontal diseases and implied to result in gingival inflammation under orthodontic appliance. rag locus is a pathogenicity island found in Porphyromonas gingivalis. Four rag locus variants are different in pathogenicity of Porphyromonas gingivalis. Moreover, there are different racial and geographic differences in distribution of rag locus genotypes. In this study, we assessed the prevalence of Porphyromonas gingivalis and rag locus genotypes in 102 gingival crevicular fluid samples from 57 cases of gingivitis patients with orthodontic appliances, 25 cases of periodontitis patients and 20 cases of periodontally healthy people through a 16S rRNA-based PCR and a multiplex PCR. The correlations between Porphyromona.gingivalis/rag locus and clinical indices were analyzed. The prevalence of Porphyromonas gingivalis and rag locus genes in periodontitis group was the highest among three groups and higher in orthodontic gingivitis than healthy people (p<0.01). An obviously positive correlation was observed between the prevalence of Porphyromonas gingivalis/rag locus and gingival index. rag-3 and rag-4 were the predominant genotypes in the patients of orthodontic gingivitis and mild-to-moderate periodontitis in Shandong. Porphyromonas.gingivalis carrying rag-1 has the strong virulence and could be associated with severe periodontitis.

Prevalence of Porphyromonas gingivalis Four rag Locus Genotypes in Patients of Orthodontic Gingivitis and Periodontitis

PubMed Central

Liu, Yi; Zhang, Yujie; Wang, Lili; Guo, Yang; Xiao, Shuiqing

2013-01-01

Porphyromonas gingivalis is considered as a major etiological agent in periodontal diseases and implied to result in gingival inflammation under orthodontic appliance. rag locus is a pathogenicity island found in Porphyromonas gingivalis. Four rag locus variants are different in pathogenicity of Porphyromonas gingivalis. Moreover, there are different racial and geographic differences in distribution of rag locus genotypes. In this study, we assessed the prevalence of Porphyromonas gingivalis and rag locus genotypes in 102 gingival crevicular fluid samples from 57 cases of gingivitis patients with orthodontic appliances, 25 cases of periodontitis patients and 20 cases of periodontally healthy people through a 16S rRNA-based PCR and a multiplex PCR. The correlations between Porphyromona.gingivalis/rag locus and clinical indices were analyzed. The prevalence of Porphyromonas gingivalis and rag locus genes in periodontitis group was the highest among three groups and higher in orthodontic gingivitis than healthy people (p<0.01). An obviously positive correlation was observed between the prevalence of Porphyromonas gingivalis/rag locus and gingival index. rag-3 and rag-4 were the predominant genotypes in the patients of orthodontic gingivitis and mild-to-moderate periodontitis in Shandong. Porphyromonas.gingivalis carrying rag-1 has the strong virulence and could be associated with severe periodontitis. PMID:23593379

Linkage of mating-type loci distinguishes bipolar from tetrapolar mating in basidiomycetous smut fungi.

PubMed Central

Bakkeren, G; Kronstad, J W

1994-01-01

Sexual compatibility requires self vs. non-self recognition. Genetically, two compatibility or mating-type systems govern recognition in heterothallic basidiomycete fungi such as the edible and woodrotting mushrooms and the economically important rust and smut phytopathogens. A bipolar system is defined by a single genetic locus (MAT) that can have two or multiple alleles. A tetrapolar system has two loci, each with two or more specificities. We have employed two species from the genus Ustilago (smut fungi) to discover a molecular explanation for the genetic difference in mating systems. Ustilago maydis, a tetrapolar species, has two genetically unlinked loci that encode the distinct mating functions of cell fusion (a locus) and subsequent sexual development and pathogenicity (b locus). We have recently described a b locus in a bipolar species, Ustilago hordei, wherein the existence of an a locus has been suspected, but not demonstrated. We report here the cloning of an allele of the a locus (a1) from U. hordei and the discovery that physical linkage of the a and b loci in this bipolar fungus accounts for the distinct mating system. Linkage establishes a large complex MAT locus in U. hordei; this locus appears to be in a region suppressed for recombination. Images PMID:7913746

Receptor protein kinase gene encoded at the self-incompatibility locus

DOEpatents

Nasrallah, June B.; Nasrallah, Mikhail E.; Stein, Joshua

1996-01-01

Described herein is a S receptor kinase gene (SRK), derived from the S locus in Brassica oleracea, having a extracellular domain highly similar to the secreted product of the S-locus glycoprotein gene.

Locus of control and peer relationships among Caucasian, Hispanic, Asian, and African American adolescents.

PubMed

Kang, Hannah Soo; Chang, Kyle Edward; Chen, Chuansheng; Greenberger, Ellen

2015-01-01

Past research has shown that locus of control plays an important role in a wide range of behaviors, such as academic achievement and positive social behaviors. However, little is known about whether locus of control plays the same role in minority adolescents' peer relationships. The current study examined ethnic differences in the associations between locus of control and peer relationships in early adolescence using samples from the Early Childhood Longitudinal Study (ECLS-K: 5,612 Caucasian, 1,562 Hispanic, 507 Asian, and 908 African-American adolescents) and the National Education Longitudinal Study (NELS: 8,484 Caucasian, 1,604 Hispanic, and 860 Asian, and 1,228 African American adolescents). Gender was approximately evenly split in both samples. The results from the two datasets were highly consistent. Significant interactions between ethnicity and locus of control indicated that having a more internal locus of control was particularly important for Caucasian students' peer relationships (ECLS-K) and social status (NELS), but less so for Asian, Hispanic, and African American students. Our findings suggest that the role of locus of control in peer relationship is contingent upon culture.

Identification of a novel locus for a USH3 like syndrome combined with congenital cataract.

PubMed

Dad, S; Østergaard, E; Thykjaer, T; Albrectsen, A; Ravn, K; Rosenberg, T; Møller, L B

2010-10-01

Usher syndrome (USH) is the most common genetic disease that causes both deafness and blindness. USH is divided into three types, USH1, USH2 and USH3, depending on the age of onset, the course of the disease, and on the degree of vestibular dysfunction. By homozygosity mapping of a consanguineous Danish family of Dutch descent, we have identified a novel locus for a rare USH3-like syndrome. The affected family members have a unique association of retinitis pigmentosa, progressive hearing impairment, vestibular dysfunction, and congenital cataract. The phenotype is similar, but not identical to that of USH3 patients, as congenital cataract has not been reported for USH3. By homozygosity mapping, we identified a 7.3 Mb locus on chromosome 15q22.2-23 with a maximum multipoint LOD score of 2.0. The locus partially overlaps with the USH1 locus, USH1H, a novel unnamed USH2 locus, and the non-syndromic deafness locus DFNB48. © 2010 John Wiley & Sons A/S.

VizieR Online Data Catalog: STAGGER-grid of 3D stellar models. V. (Chiavassa+, 2018)

NASA Astrophysics Data System (ADS)

Chiavassa, A.; Casagrande, L.; Collet, R.; Magic, Z.; Bigot, L.; Thevenin, F.; Asplund, M.

2018-01-01

Table B0: RHD simulations' stellar parameters, bolometric magnitude, and bolometric correction for Johnson-Cousins, 2MASS, SDSS (columns 13 to 17), and Gaia systems Table 4: RHD simulations' stellar parameters, bolometric magnitude, and bolometric correction for SkyMapper photometric system, and Stroemgren index b-y, m1=(v-b)-(b-y), and c1=(u-v)-(v-b) Table 5: RHD simulations' stellar parameters, bolometric magnitude, and bolometric correction for the HST-WFC3 in VEGA system Table 6: RHD simulations' stellar parameters, bolometric magnitude, and bolometric correction for the HST-WFC3 in ST system Table 7: RHD simulations' stellar parameters, bolometric magnitude, and bolometric correction for the HST-WFC3 in AB system (5 data files).

Meta-analysis of Parkinson's disease: identification of a novel locus, RIT2.

PubMed

Pankratz, Nathan; Beecham, Gary W; DeStefano, Anita L; Dawson, Ted M; Doheny, Kimberly F; Factor, Stewart A; Hamza, Taye H; Hung, Albert Y; Hyman, Bradley T; Ivinson, Adrian J; Krainc, Dmitri; Latourelle, Jeanne C; Clark, Lorraine N; Marder, Karen; Martin, Eden R; Mayeux, Richard; Ross, Owen A; Scherzer, Clemens R; Simon, David K; Tanner, Caroline; Vance, Jeffery M; Wszolek, Zbigniew K; Zabetian, Cyrus P; Myers, Richard H; Payami, Haydeh; Scott, William K; Foroud, Tatiana

2012-03-01

Genome-wide association (GWAS) methods have identified genes contributing to Parkinson's disease (PD); we sought to identify additional genes associated with PD susceptibility. A 2-stage design was used. First, individual level genotypic data from 5 recent PD GWAS (Discovery Sample: 4,238 PD cases and 4,239 controls) were combined. Following imputation, a logistic regression model was employed in each dataset to test for association with PD susceptibility and results from each dataset were meta-analyzed. Second, 768 single-nucleotide polymorphisms (SNPs) were genotyped in an independent Replication Sample (3,738 cases and 2,111 controls). Genome-wide significance was reached for SNPs in SNCA (rs356165; G: odds ratio [OR]=1.37; p=9.3×10(-21)), MAPT (rs242559; C: OR=0.78; p=1.5×10(-10)), GAK/DGKQ (rs11248051; T: OR=1.35; p=8.2×10(-9)/rs11248060; T: OR=1.35; p=2.0×10(-9)), and the human leukocyte antigen (HLA) region (rs3129882; A: OR=0.83; p=1.2×10(-8)), which were previously reported. The Replication Sample confirmed the associations with SNCA, MAPT, and the HLA region and also with GBA (E326K; OR=1.71; p=5×10(-8) Combined Sample) (N370; OR=3.08; p=7×10(-5) Replication sample). A novel PD susceptibility locus, RIT2, on chromosome 18 (rs12456492; p=5×10(-5) Discovery Sample; p=1.52×10(-7) Replication sample; p=2×10(-10) Combined Sample) was replicated. Conditional analyses within each of the replicated regions identified distinct SNP associations within GBA and SNCA, suggesting that there may be multiple risk alleles within these genes. We identified a novel PD susceptibility locus, RIT2, replicated several previously identified loci, and identified more than 1 risk allele within SNCA and GBA. Copyright © 2012 American Neurological Association.

Exome Array Analysis Identifies a Common Variant in IL27 Associated with Chronic Obstructive Pulmonary Disease

PubMed Central

Parker, Margaret M.; Chen, Han; Lao, Taotao; Hardin, Megan; Qiao, Dandi; Hawrylkiewicz, Iwona; Sliwinski, Pawel; Yim, Jae-Joon; Kim, Woo Jin; Kim, Deog Kyeom; Castaldi, Peter J.; Hersh, Craig P.; Morrow, Jarrett; Celli, Bartolome R.; Pinto-Plata, Victor M.; Criner, Gerald J.; Marchetti, Nathaniel; Bueno, Raphael; Agustí, Alvar; Make, Barry J.; Crapo, James D.; Calverley, Peter M.; Donner, Claudio F.; Lomas, David A.; Wouters, Emiel F. M.; Vestbo, Jorgen; Paré, Peter D.; Levy, Robert D.; Rennard, Stephen I.; Zhou, Xiaobo; Laird, Nan M.; Lin, Xihong; Beaty, Terri H.; Silverman, Edwin K.

2016-01-01

Rationale: Chronic obstructive pulmonary disease (COPD) susceptibility is in part related to genetic variants. Most genetic studies have been focused on genome-wide common variants without a specific focus on coding variants, but common and rare coding variants may also affect COPD susceptibility. Objectives: To identify coding variants associated with COPD. Methods: We tested nonsynonymous, splice, and stop variants derived from the Illumina HumanExome array for association with COPD in five study populations enriched for COPD. We evaluated single variants with a minor allele frequency greater than 0.5% using logistic regression. Results were combined using a fixed effects meta-analysis. We replicated novel single-variant associations in three additional COPD cohorts. Measurements and Main Results: We included 6,004 control subjects and 6,161 COPD cases across five cohorts for analysis. Our top result was rs16969968 (P = 1.7 × 10−14) in CHRNA5, a locus previously associated with COPD susceptibility and nicotine dependence. Additional top results were found in AGER, MMP3, and SERPINA1. A nonsynonymous variant, rs181206, in IL27 (P = 4.7 × 10−6) was just below the level of exome-wide significance but attained exome-wide significance (P = 5.7 × 10−8) when combined with results from other cohorts. Gene expression datasets revealed an association of rs181206 and the surrounding locus with expression of multiple genes; several were differentially expressed in COPD lung tissue, including TUFM. Conclusions: In an exome array analysis of COPD, we identified nonsynonymous variants at previously described loci and a novel exome-wide significant variant in IL27. This variant is at a locus previously described in genome-wide associations with diabetes, inflammatory bowel disease, and obesity and appears to affect genes potentially related to COPD pathogenesis. PMID:26771213

Quantitative Trait Locus Analysis of SIX1-SIX6 with Retinal Nerve Fiber Layer Thickness in Individuals of European Descent

PubMed Central

Kuo, Jane Z.; Zangwill, Linda M.; Medeiros, Felipe A.; Liebmann, Jeffery M.; Girkin, Christopher A.; Hammel, Na’ama; Rotter, Jerome I.; Weinreb, Robert N.

2015-01-01

Purpose To perform a quantitative trait locus (QTL) analysis and evaluate whether a locus between SIX1 and SIX6 is associated with retinal nerve fiber layer (RNFL) thickness in individuals of European descent. Design Observational, multi-center, cross-sectional study. Methods 231 participants were recruited from the Diagnostic Innovations in Glaucoma Study and the African Descent and Glaucoma Evaluation Study. Association of rs10483727 in SIX1-SIX6 with global and sectoral RNFL thickness was performed. Quantitative trait analysis with the additive model of inheritance was analyzed using linear regression. Trend analysis was performed to evaluate the mean global and sectoral RNFL thickness with 3 genotypes of interest (T/T, C/T, C/C). All models were adjusted for age and gender. Results Direction of association between T allele and RNFL thickness was consistent in the global and different sectoral RNFL regions. Each copy of the T risk allele in rs10483727 was associated with −0.16 μm thinner global RNFL thickness (β=−0.16, 95% CI: −0.28 to −0.03; P=0.01). Similar patterns were found for the sectoral regions, including inferior (P=0.03), inferior-nasal (P=0.017), superior-nasal (P=0.0025), superior (P=0.002) and superior-temporal (P=0.008). The greatest differences were observed in the superior and inferior quadrants, supporting clinical observations for RNFL thinning in glaucoma. Thinner global RNFL was found in subjects with T/T genotypes compared to subjects with C/T and C/C genotypes (P=0.044). Conclusions Each copy of the T risk allele has an additive effect and was associated with thinner global and sectoral RNFL. Findings from this QTL analysis further support a genetic contribution to glaucoma pathophysiology. PMID:25849520

Role of a Genetic Variant on the 15q25.1 Lung Cancer Susceptibility Locus in Smoking-Associated Nasopharyngeal Carcinoma

PubMed Central

Ji, Xuemei; Zhang, Weidong; Gui, Jiang; Fan, Xia; Zhang, Weiwei; Li, Yafang; An, Guangyu; Zhu, Dakai; Hu, Qiang

2014-01-01

Background The 15q25.1 lung cancer susceptibility locus, containing CHRNA5, could modify lung cancer susceptibility and multiple smoking related phenotypes. However, no studies have investigated the association between CHRNA5 rs3841324, which has been proven to have the highest association with CHRNA5 mRNA expression, and the risk of other smoking-associated cancers, except lung cancer. In the current study we examined the association between rs3841324 and susceptibility to smoking-associated nasopharyngeal carcinoma (NPC). Methods In this case-control study we genotyped the CHRNA5 rs3841324 polymorphism with 400 NPC cases and 491 healthy controls who were Han Chinese and frequency-matched by age (±5 years), gender, and alcohol consumption. Univariate and multivariate logistic regression analyses were used to calculate the odds ratio (OR) and 95% confidence intervals (95% CI). Results We found that individuals with CHRNA5 rs3841324 combined variant genotypes (ins/del+del/del) had a >1.5-fold elevated risk for NPC than those with the ins/ins genotype (adjusted OR = 1.52; 95% CI, 1.16–2.00), especially among ever smokers (adjusted OR = 2.07; 95% CI, 1.23–3.48). The combined variant genotypes acted jointly with cigarette smoking to contribute to a 4.35-fold increased NPC risk (adjusted OR = 4.35; 95% CI, 2.57–7.38). There was a dose-response relationship between deletion alleles and NPC susceptibility (trend test, P = 0.011). Conclusions Our results suggest that genetic variants on the 15q25.1 lung cancer susceptibility locus may influence susceptibility to NPC, particularly for smoking-associated NPC. Such work may be helpful to facilitate an understanding of the etiology of smoking-associated cancers and improve prevention efforts. PMID:25329654

Resistance to temptation: the interaction of external and internal control on alcohol use during residential treatment for alcohol use disorder.

PubMed

Soravia, Leila M; Schläfli, Katrin; Stutz, Sonja; Rösner, Susanne; Moggi, Franz

2015-11-01

There is evidence that drinking during residential treatment is related to various factors, such as patients' general control beliefs and self-efficacy, as well as to external control of alcohol use by program's staff and situations where there is temptation to drink. As alcohol use during treatment has been shown to be associated with the resumption of alcohol use after discharge from residential treatment, we aimed to investigate how these variables are related to alcohol use during abstinence-oriented residential treatment programs for alcohol use disorders (AUD). In total, 509 patients who entered 1 of 2 residential abstinence-oriented treatment programs for AUD were included in the study. After detoxification, patients completed a standardized diagnostic procedure including interviews and questionnaires. Drinking was assessed by patients' self-report of at least 1 standard drink or by positive breathalyzer testing. The 2 residential programs were categorized as high or low control according to the average number of tests per patient. Regression analysis revealed a significant interaction effect between internal and external control suggesting that patients with high internal locus of control and high frequency of control by staff demonstrated the least alcohol use during treatment (16.7%) while patients with low internal locus of control in programs with low external control were more likely to use alcohol during treatment (45.9%). No effects were found for self-efficacy and temptation. As alcohol use during treatment is most likely associated with poor treatment outcomes, external control may improve treatment outcomes and particularly support patients with low internal locus of control, who show the highest risk for alcohol use during treatment. High external control may complement high internal control to improve alcohol use prevention while in treatment. Copyright © 2015 The Authors. Alcoholism: Clinical and Experimental Research published by Wiley Periodicals, Inc. on behalf of Research Society on Alcoholism.

Meta-analysis of Parkinson disease: Identification of a novel locus, RIT2

PubMed Central

Pankratz, Nathan; Beecham, Gary W.; DeStefano, Anita L.; Dawson, Ted M.; Doheny, Kimberly F.; Factor, Stewart A.; Hamza, Taye H.; Hung, Albert Y.; Hyman, Bradley T.; Ivinson, Adrian J.; Krainc, Dmitri; Latourelle, Jeanne C.; Clark, Lorraine N.; Marder, Karen; Martin, Eden R.; Mayeux, Richard; Ross, Owen A.; Scherzer, Clemens R.; Simon, David K.; Tanner, Caroline; Vance, Jeffery M.; Wszolek, Zbigniew K.; Zabetian, Cyrus P.; Myers, Richard H.; Payami, Haydeh; Scott, William K.; Foroud, Tatiana

2011-01-01

Objective Genome-wide association (GWAS) methods have identified genes contributing to Parkinson disease (PD); we sought to identify additional genes associated with PD susceptibility. Methods A two stage design was used. First, individual level genotypic data from five recent PD GWAS (Discovery Sample: 4,238 PD cases and 4,239 controls) were combined. Following imputation, a logistic regression model was employed in each dataset to test for association with PD susceptibility and results from each dataset were meta-analyzed. Second, 768 SNPs were genotyped in an independent Replication Sample (3,738 cases and 2,111 controls). Results Genome-wide significance was reached for SNPs in SNCA (rs356165, G: odds ratio (OR)=1.37; p=9.3 × 10−21), MAPT (rs242559, C: OR=0.78; p=1.5 × 10−10), GAK/DGKQ (rs11248051, T:OR=1.35; p=8.2 × 10−9/ rs11248060, T: OR=1.35; p=2.0×10−9), and the HLA region (rs3129882, A: OR=0.83; p=1.2 × 10−8), which were previously reported. The Replication Sample confirmed the associations with SNCA, MAPT, and the HLA region and also with GBA (E326K OR=1.71; p=5 × 10−8 Combined Sample) (N370 OR=3.08; p=7 × 10−5 Replication sample). A novel PD susceptibility locus, RIT2, on chromosome 18 (rs12456492; p=5 × 10−5 Discovery Sample; p=1.52 × 10−7 Replication sample; p=2 × 10−10 Combined Sample) was replicated. Conditional analyses within each of the replicated regions identified distinct SNP associations within GBA and SNCA, suggesting that there may be multiple risk alleles within these genes. Interpretation We identified a novel PD susceptibility locus, RIT2, replicated several previously identified loci, and identified more than one risk allele within SNCA and GBA. PMID:22451204

The Longevity of Hippocampus-Dependent Memory Is Orchestrated by the Locus Coeruleus-Noradrenergic System

PubMed Central

2017-01-01

The locus coeruleus is connected to the dorsal hippocampus via strong fiber projections. It becomes activated after arousal and novelty, whereupon noradrenaline is released in the hippocampus. Noradrenaline from the locus coeruleus is involved in modulating the encoding, consolidation, retrieval, and reversal of hippocampus-based memory. Memory storage can be modified by the activation of the locus coeruleus and subsequent facilitation of hippocampal long-term plasticity in the forms of long-term depression and long-term potentiation. Recent evidence indicates that noradrenaline and dopamine are coreleased in the hippocampus from locus coeruleus terminals, thus fostering neuromodulation of long-term synaptic plasticity and memory. Noradrenaline is an inductor of epigenetic modifications regulating transcriptional control of synaptic long-term plasticity to gate the endurance of memory storage. In conclusion, locus coeruleus activation primes the persistence of hippocampus-based long-term memory. PMID:28695015

A silent allele in the locus D5S818 contained within the PowerPlex®21 PCR Amplification Kit.

PubMed

Chen, Ling; Tai, Yunchun; Qiu, Pingming; Du, Weian; Liu, Chao

2015-11-01

Three paternity tests cases were found with a single locus mismatch at the locus D5S818 with PowerPlex®21 PCR Amplification Kit (Promega). Forward and reverse primers were redesigned to type the samples again and to evaluate if there were alleles dropped out. The results showed the existence of a silent allele 12 in all the three families, due to a point mutation that changed cytosine to adenine at 90 nucleotides upstream from the 5' end of the AGAT repeat sequences in all the six individuals. A single locus mismatch due to a silent allele may occur in any locus using any kit. Therefore, we recommend using multiple kits to confirm the results in paternity testing cases with mismatches, especially when there is a single locus mismatch with homozygote involved. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

The Effects of Religion and Locus of Control on Perception of Mental Illness.

PubMed

Amedome, Sedem Nunyuia; Bedi, Innocent Kwame

2018-06-23

The study investigated the influence of religion and locus of control on perception of mental illness. Specifically, the study explored the relationship between religiosity and perception of mental illness, differences in perception by internals and externals, the effect of knowledge on perception of mental illness and the interactive effect of religiosity and locus of control on perception of mental illness. Data were collected from 200 participants in the Volta Region of Ghana. Three hypotheses were tested in the study using a battery of tests. It was observed that people with internal locus of control perceive mental patients positively than those with external locus of control. A significant interactive effect between religiosity and locus of control on perception of mental illness was observed. Religiosity significantly relates to perception of mental illness. The results and implications are discussed for further studies.

The Dragonfly Nearby Galaxies Survey. IV. A Giant Stellar Disk in NGC 2841

NASA Astrophysics Data System (ADS)

Zhang, Jielai; Abraham, Roberto; van Dokkum, Pieter; Merritt, Allison; Janssens, Steven

2018-03-01

Neutral gas is commonly believed to dominate over stars in the outskirts of galaxies, and investigations of the disk-halo interface are generally considered to be in the domain of radio astronomy. This may simply be a consequence of the fact that deep H I observations typically probe to a lower-mass surface density than visible wavelength data. This paper presents low-surface-brightness, optimized visible wavelength observations of the extreme outskirts of the nearby spiral galaxy NGC 2841. We report the discovery of an enormous low-surface brightness stellar disk in this object. When azimuthally averaged, the stellar disk can be traced out to a radius of ∼70 kpc (5 R 25 or 23 inner disk scale lengths). The structure in the stellar disk traces the morphology of H I emission and extended UV emission. Contrary to expectations, the stellar mass surface density does not fall below that of the gas mass surface density at any radius. In fact, at all radii greater than ∼20 kpc, the ratio of the stellar mass to gas mass surface density is a constant 3:1. Beyond ∼30 kpc, the low-surface-brightness stellar disk begins to warp, which may be an indication of a physical connection between the outskirts of the galaxy and infall from the circumgalactic medium. A combination of stellar migration, accretion, and in situ star formation might be responsible for building up the outer stellar disk, but whatever mechanisms formed the outer disk must also explain the constant ratio between stellar and gas mass in the outskirts of this galaxy.

PHAT+MaNGA: Using resolved stellar populations to improve the recovery of star formation histories from galaxy spectra

NASA Astrophysics Data System (ADS)

Byler, Nell

2017-08-01

Stellar Population Synthesis (SPS) models are routinely used to interpret extragalactic observations at all redshifts. Currently, the dominant source of uncertainty in SPS modeling lies in the degeneracies associated with synthesizing and fitting complex stellar populations to observed galaxy spectra. To remedy this, we propose an empirical calibration of SPS models using resolved stellar population observations from Hubble Space Telescope (HST) to constrain the stellar masses, ages, and star formation histories (SFHs) in regions matched to 2D spectroscopic observations from MaNGA. We will take advantage of the state of the art observations from the Panchromatic Hubble Andromeda Treasury (PHAT), which maps the dust content, history of chemical enrichment, and history of star formation across the disk of M31 in exquisite detail. Recently, we have coupled these observations with an unprecedented, spatially-resolved suite of IFU observations from MaNGA. With these two comprehensive data sets we can use the true underlying stellar properties from PHAT to properly interpret the aperture-matched integrated spectra from MaNGA. Our MaNGA observations target 20 regions within the PHAT footprint that fully sample the available range in metallicity, SFR, dust content, and stellar density. This transformative dataset will establish a comprehensive link between resolved stellar populations and the inferred properties of unresolved stellar populations across astrophysically important environments. The net data product will be a library of galaxy spectra matched to the true underlying stellar properties, a comparison set that has lasting legacy value for the extragalactic community.

New theory of stellar convection without the mixing-length parameter: new stellar atmosphere model

NASA Astrophysics Data System (ADS)

Pasetto, Stefano; Chiosi, Cesare; Cropper, Mark; Grebel, Eva K.

2018-01-01

Stellar convection is usually described by the mixing-length theory, which makes use of the mixing-length scale factor to express the convective flux, velocity, and temperature gradients of the convective elements and stellar medium. The mixing-length scale is proportional to the local pressure scale height of the star, and the proportionality factor (i.e. mixing-length parameter) is determined by comparing the stellar models to some calibrator, i.e. the Sun. No strong arguments exist to suggest that the mixing-length parameter is the same in all stars and all evolutionary phases and because of this, all stellar models in the literature are hampered by this basic uncertainty. In a recent paper [1] we presented a new theory that does not require the mixing length parameter. Our self-consistent analytical formulation of stellar convection determines all the properties of stellar convection as a function of the physical behavior of the convective elements themselves and the surrounding medium. The new theory of stellar convection is formulated starting from a conventional solution of the Navier-Stokes/Euler equations expressed in a non-inertial reference frame co-moving with the convective elements. The motion of stellar convective cells inside convective-unstable layers is fully determined by a new system of equations for convection in a non-local and time-dependent formalism. The predictions of the new theory are compared with those from the standard mixing-length paradigm with positive results for atmosphere models of the Sun and all the stars in the Hertzsprung-Russell diagram.

Star-forming galaxies in intermediate-redshift clusters: stellar versus dynamical masses of luminous compact blue galaxies

NASA Astrophysics Data System (ADS)

Randriamampandry, S. M.; Crawford, S. M.; Bershady, M. A.; Wirth, G. D.; Cress, C. M.

2017-10-01

We investigate the stellar masses of the class of star-forming objects known as luminous compact blue galaxies (LCBGs) by studying a sample of galaxies in the distant cluster MS 0451.6-0305 at z ≈ 0.54 with ground-based multicolour imaging and spectroscopy. For a sample of 16 spectroscopically confirmed cluster LCBGs (colour B - V < 0.5, surface brightness μB < 21 mag arcsec-2 and magnitude MB < -18.5), we measure stellar masses by fitting spectral energy distribution (SED) models to multiband photometry, and compare with dynamical masses [determined from velocity dispersion in the range 10 < σv(km s- 1) < 80] we previously obtained from their emission-line spectra. We compare two different stellar population models that measure stellar mass in star-bursting galaxies, indicating correlations between the stellar age, extinction and stellar mass derived from the two different SED models. The stellar masses of cluster LCBGs are distributed similarly to those of field LCBGs, but the cluster LCBGs show lower dynamical-to-stellar mass ratios (Mdyn/M⋆ = 2.6) than their field LCBG counterparts (Mdyn/M⋆ = 4.8), echoing trends noted previously in low-redshift dwarf elliptical galaxies. Within this limited sample, the specific star formation rate declines steeply with increasing mass, suggesting that these cluster LCBGs have undergone vigorous star formation.

Detection of a molecular deletion at the DXS732 locus in a patient with X-linked hypohidrotic ectodermal dysplasia (EDA), with the identification of a unique junctional fragment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zonana, J.; Gault, J.; Jones, M.

1993-01-01

X-linked hypohidrotic ectodermal dysplasia (EDA) has been localized to the Xq12-q13.1. A panel of genomic DNA samples from 80 unrelated males with EDA has been screened for deletions at seven genetic loci within the Xq12-13 region. A single individual was identified with a deletion at the DXS732 locus by hybridization with the mouse genomic probe pcos169E/4. This highly conserved DNA probe is from locus DXCrc169, which is tightly linked to the Ta locus, the putative mouse homologue of EDA. The proband had the classical phenotype of EDA, with no other phenotypic abnormalities, and a normal cytogenetic analysis. A human genomicmore » DNA clone, homologous to pcos169E/4, was isolated from a human X-chromosome cosmid library. On hybridization with the cosmid, the proband was found to be only partially deleted at the DXS732 locus, with a unique junctional fragment identified in the proband and in three of his maternal relatives. This is the first determination of carrier status for EDA in females, by direct mutation analysis. Failure to detect deletion of the other loci tested in the proband suggests that the DXS732 locus is the closest known locus to the EDA gene. Since the DXS732 locus contains a highly conserved sequence, it must be considered to be a candidate locus for the EDA gene itself. 18 refs., 3 figs., 1 tab.« less

The calculation and publication of a grid of line-blanketed model stellar atmospheres

NASA Technical Reports Server (NTRS)

Avrett, E. H.

1972-01-01

The luminosity, mass, and elemental abundances, as well as other properties of each star are studied in order to locate them in an evolutionary pattern. A method for determining the flux, gravity, and abundances at the stellar surface is the construction of theoretical stellar atmospheric models that predict the observed energy distribution and detailed stellar spectrum.

The distribution of stars most likely to harbor intelligent life.

PubMed

Whitmire, Daniel P; Matese, John J

2009-09-01

Simple heuristic models and recent numerical simulations show that the probability of habitable planet formation increases with stellar mass. We combine those results with the distribution of main-sequence stellar masses to obtain the distribution of stars most likely to possess habitable planets as a function of stellar lifetime. We then impose the self-selection condition that intelligent observers can only find themselves around a star with a lifetime greater than the time required for that observer to have evolved, T(i). This allows us to obtain the stellar timescale number distribution for a given value of T(i). Our results show that for habitable planets with a civilization that evolved at time T(i) = 4.5 Gyr the median stellar lifetime is 13 Gyr, corresponding approximately to a stellar type of G5, with two-thirds of the stars having lifetimes between 7 and 30 Gyr, corresponding approximately to spectral types G0-K5. For other values of T(i) the median stellar lifetime changes by less than 50%.

A GRID OF THREE-DIMENSIONAL STELLAR ATMOSPHERE MODELS OF SOLAR METALLICITY. I. GENERAL PROPERTIES, GRANULATION, AND ATMOSPHERIC EXPANSION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trampedach, Regner; Asplund, Martin; Collet, Remo

2013-05-20

Present grids of stellar atmosphere models are the workhorses in interpreting stellar observations and determining their fundamental parameters. These models rely on greatly simplified models of convection, however, lending less predictive power to such models of late-type stars. We present a grid of improved and more reliable stellar atmosphere models of late-type stars, based on deep, three-dimensional (3D), convective, stellar atmosphere simulations. This grid is to be used in general for interpreting observations and improving stellar and asteroseismic modeling. We solve the Navier Stokes equations in 3D and concurrent with the radiative transfer equation, for a range of atmospheric parameters,more » covering most of stellar evolution with convection at the surface. We emphasize the use of the best available atomic physics for quantitative predictions and comparisons with observations. We present granulation size, convective expansion of the acoustic cavity, and asymptotic adiabat as functions of atmospheric parameters.« less

Locus of control, perceived parenting style, and symptoms of anxiety and depression in children with Tourette's syndrome.

PubMed

Cohen, Esther; Sade, Michal; Benarroch, Fortu; Pollak, Yehuda; Gross-Tsur, Varda

2008-08-01

This study explored the contribution of two psychosocial factors, locus of control (LOC) and perceived parenting style, to symptoms of internalizing disorders in children with Tourette syndrome (TS). This contribution was further evaluated in relation to TS severity. Sixty-five children (53 boys, 12 girls) ages 9.0-16.9 years, of normal intelligence, completed questionnaires evaluating their depression and anxiety symptoms, LOC, and maternal parenting style. Their mothers rated TS severity, determined by tic severity, symptoms of attention-deficit hyperactivity disorder (ADHD) and obsessive compulsive symptoms (OCS). Higher rates of symptoms of anxiety and depression were associated with a more external LOC and a more rejecting and controlling parenting style. Additionally, depression correlated significantly with tic severity, ADHD and OCS, whereas anxiety correlated only with ADHD symptoms and OCS, but not with tics. Regression analyses showed that LOC, OCS and ADHD symptoms each significantly contributed to predicting anxiety level, whereas LOC and ADHD symptoms significantly contributed to predicting depression symptoms. Rates of symptoms of anxiety and depression in children with TS are markedly influenced by psychosocial factors, extending beyond the influence of ADHD and OCD, both common comorbid disorders in TS. An internal LOC, which is associated with an accepting and autonomy-granting parenting style, appears to be a protective factor against anxiety and depression.

A TNF region haplotype offers protection from typhoid fever in Vietnamese patients

PubMed Central

2009-01-01

The genomic region surrounding the TNF locus on human chromosome 6 has previously been associated with typhoid fever in Vietnam. We used a haplotypic approach to understand this association further. Eighty single nucleotide polymorphisms (SNPs) spanning a 150 kb region were genotyped in 95 Vietnamese individuals (typhoid case/mother/father trios). A subset of data from 33 SNPs with a minor allele frequency of >4.3% was used to construct haplotypes. Fifteen SNPs, which tagged the 42 constructed haplotypes were selected. The haplotype tagging SNPs (T1-T15) were genotyped in 380 confirmed typhoid cases and 380 Vietnamese ethnically matched controls. Allelic frequencies of seven SNPs (T1, T2, T3, T5, T6, T7, T8) were significantly different between typhoid cases and controls. Logistic regression results support the hypothesis that there is just one signal associated with disease at this locus. Haplotype-based analysis of the tag SNPs provided positive evidence of association with typhoid (posterior probability 0.821). The analysis highlighted a low-risk cluster of haplotypes that each carry the minor allele of T1 or T7, but not both, and otherwise carry the combination of alleles *12122*1111 at T1-T11, further supporting the one associated signal hypothesis. Finally, individuals that carry the typhoid fever protective haplotype *12122*1111 also produce a relatively low TNF-α response to LPS. PMID:17503085

Joint analysis of three genome-wide association studies of esophageal squamous cell carcinoma in Chinese populations.

PubMed

Wu, Chen; Wang, Zhaoming; Song, Xin; Feng, Xiao-Shan; Abnet, Christian C; He, Jie; Hu, Nan; Zuo, Xian-Bo; Tan, Wen; Zhan, Qimin; Hu, Zhibin; He, Zhonghu; Jia, Weihua; Zhou, Yifeng; Yu, Kai; Shu, Xiao-Ou; Yuan, Jian-Min; Zheng, Wei; Zhao, Xue-Ke; Gao, She-Gan; Yuan, Zhi-Qing; Zhou, Fu-You; Fan, Zong-Min; Cui, Ji-Li; Lin, Hong-Li; Han, Xue-Na; Li, Bei; Chen, Xi; Dawsey, Sanford M; Liao, Linda; Lee, Maxwell P; Ding, Ti; Qiao, You-Lin; Liu, Zhihua; Liu, Yu; Yu, Dianke; Chang, Jiang; Wei, Lixuan; Gao, Yu-Tang; Koh, Woon-Puay; Xiang, Yong-Bing; Tang, Ze-Zhong; Fan, Jin-Hu; Han, Jing-Jing; Zhou, Sheng-Li; Zhang, Peng; Zhang, Dong-Yun; Yuan, Yuan; Huang, Ying; Liu, Chunling; Zhai, Kan; Qiao, Yan; Jin, Guangfu; Guo, Chuanhai; Fu, Jianhua; Miao, Xiaoping; Lu, Changdong; Yang, Haijun; Wang, Chaoyu; Wheeler, William A; Gail, Mitchell; Yeager, Meredith; Yuenger, Jeff; Guo, Er-Tao; Li, Ai-Li; Zhang, Wei; Li, Xue-Min; Sun, Liang-Dan; Ma, Bao-Gen; Li, Yan; Tang, Sa; Peng, Xiu-Qing; Liu, Jing; Hutchinson, Amy; Jacobs, Kevin; Giffen, Carol; Burdette, Laurie; Fraumeni, Joseph F; Shen, Hongbing; Ke, Yang; Zeng, Yixin; Wu, Tangchun; Kraft, Peter; Chung, Charles C; Tucker, Margaret A; Hou, Zhi-Chao; Liu, Ya-Li; Hu, Yan-Long; Liu, Yu; Wang, Li; Yuan, Guo; Chen, Li-Sha; Liu, Xiao; Ma, Teng; Meng, Hui; Sun, Li; Li, Xin-Min; Li, Xiu-Min; Ku, Jian-Wei; Zhou, Ying-Fa; Yang, Liu-Qin; Wang, Zhou; Li, Yin; Qige, Qirenwang; Yang, Wen-Jun; Lei, Guang-Yan; Chen, Long-Qi; Li, En-Min; Yuan, Ling; Yue, Wen-Bin; Wang, Ran; Wang, Lu-Wen; Fan, Xue-Ping; Zhu, Fang-Heng; Zhao, Wei-Xing; Mao, Yi-Min; Zhang, Mei; Xing, Guo-Lan; Li, Ji-Lin; Han, Min; Ren, Jing-Li; Liu, Bin; Ren, Shu-Wei; Kong, Qing-Peng; Li, Feng; Sheyhidin, Ilyar; Wei, Wu; Zhang, Yan-Rui; Feng, Chang-Wei; Wang, Jin; Yang, Yu-Hua; Hao, Hong-Zhang; Bao, Qi-De; Liu, Bao-Chi; Wu, Ai-Qun; Xie, Dong; Yang, Wan-Cai; Wang, Liang; Zhao, Xiao-Hang; Chen, Shu-Qing; Hong, Jun-Yan; Zhang, Xue-Jun; Freedman, Neal D; Goldstein, Alisa M; Lin, Dongxin; Taylor, Philip R; Wang, Li-Dong; Chanock, Stephen J

2014-09-01

We conducted a joint (pooled) analysis of three genome-wide association studies (GWAS) of esophageal squamous cell carcinoma (ESCC) in individuals of Chinese ancestry (5,337 ESCC cases and 5,787 controls) with 9,654 ESCC cases and 10,058 controls for follow-up. In a logistic regression model adjusted for age, sex, study and two eigenvectors, two new loci achieved genome-wide significance, marked by rs7447927 at 5q31.2 (per-allele odds ratio (OR) = 0.85, 95% confidence interval (CI) = 0.82-0.88; P = 7.72 × 10(-20)) and rs1642764 at 17p13.1 (per-allele OR = 0.88, 95% CI = 0.85-0.91; P = 3.10 × 10(-13)). rs7447927 is a synonymous SNP in TMEM173, and rs1642764 is an intronic SNP in ATP1B2, near TP53. Furthermore, a locus in the HLA class II region at 6p21.32 (rs35597309) achieved genome-wide significance in the two populations at highest risk for ESSC (OR = 1.33, 95% CI = 1.22-1.46; P = 1.99 × 10(-10)). Our joint analysis identifies new ESCC susceptibility loci overall as well as a new locus unique to the population in the Taihang Mountain region at high risk of ESCC.

The Role of Internal Health Locus of Control in Relation to Self-Rated Health in Older Adults.

PubMed

Zhang, Anao; Jang, Yuri

2017-01-01

The present study examined how internal health locus of control is associated with older adults' self-rated health. Multivariate analyses with older participants (aged ≥ 60) in the MIDUS II (n = 1,533) showed that internal health locus of control was not only directly associated with positive ratings of health but also interacted with gender and race. The positive impact of internal health locus of control on self-rated health was particularly greater in females and Whites than their counterparts. Findings highlight the important role of internal health locus of control in the psychological mechanism of health and call attention to group-specific strategies for health promotion.

Multidimensional profiles of health locus of control in Hispanic Americans

PubMed Central

Champagne, Brian R; Fox, Rina S; Mills, Sarah D; Sadler, Georgia Robins; Malcarne, Vanessa L

2016-01-01

Latent profile analysis identified health locus of control profiles among 436 Hispanic Americans who completed the Multidimensional Health Locus of Control scales. Results revealed four profiles: Internally Oriented-Weak, -Moderate, -Strong, and Externally Oriented. The profile groups were compared on sociocultural and demographic characteristics, health beliefs and behaviors, and physical and mental health outcomes. The Internally Oriented-Strong group had less cancer fatalism, religiosity, and equity health attributions, and more alcohol consumption than the other three groups; the Externally Oriented group had stronger equity health attributions and less alcohol consumption. Deriving multidimensional health locus of control profiles through latent profile analysis allows examination of the relationships of health locus of control subtypes to health variables. PMID:25855212

Improving 1D Stellar Models with 3D Atmospheres

NASA Astrophysics Data System (ADS)

Mosumgaard, Jakob Rørsted; Silva Aguirre, Víctor; Weiss, Achim; Christensen-Dalsgaard, Jørgen; Trampedach, Regner

2017-10-01

Stellar evolution codes play a major role in present-day astrophysics, yet they share common issues. In this work we seek to remedy some of those by the use of results from realistic and highly detailed 3D hydrodynamical simulations of stellar atmospheres. We have implemented a new temperature stratification extracted directly from the 3D simulations into the Garching Stellar Evolution Code to replace the simplified atmosphere normally used. Secondly, we have implemented the use of a variable mixing-length parameter, which changes as a function of the stellar surface gravity and temperature - also derived from the 3D simulations. Furthermore, to make our models consistent, we have calculated new opacity tables to match the atmospheric simulations. Here, we present the modified code and initial results on stellar evolution using it.

Stellar Rotation: New Insight from CoRoT

NASA Astrophysics Data System (ADS)

Catala, C.; Goupil, M. J.; Michel, E.; Baglin, A.; de Medeiros, J. Renan; Gondoin, Ph.

2009-02-01

We present an overview of the new insight provided by the CoRoT satellite on stellar rotation. Thanks to its ultra-high precision, high duty cycle, long photometric monitoring of thousands of stars, CoRoT gives us a powerful tool to study stellar rotational modulation, and therefore to measure stellar rotational periods and to study active structures at the surface of stars. This paper presents preliminary results concerning this type of study. CoRoT will also provide us with an insight of internal stellar rotation via the measurement and exploitation of rotational splittings of oscillation modes. This approach to stellar rotation with CoRoT will require a careful analysis of the oscillation power spectra, which is in progress, but prospects for such measurements are presented.

Myostatin-deficiency in mice increases global gene expression at the Dlk1-Dio3 locus in the skeletal muscle

PubMed Central

Hitachi, Keisuke; Tsuchida, Kunihiro

2017-01-01

Myostatin, a member of the transforming growth factor-beta superfamily, is a negative regulator of skeletal muscle growth and development. Myostatin inhibition leads to increased skeletal muscle mass in mammals; hence, myostatin is considered a potential therapeutic target for skeletal muscle wasting. However, downstream molecules of myostatin in the skeletal muscle have not been fully elucidated. Here, we identified the Dlk1-Dio3 locus at the mouse chromosome 12qF1, also called as the callipyge locus in sheep, as a novel downstream target of myostatin. In skeletal muscle of myostatin knockout mice, the expression of mature miRNAs at the Dlk1-Dio3 locus was significantly increased. The increased miRNA levels are caused by the transcriptional activation of the Dlk1-Dio3 locus, because a significant increase in the primary miRNA transcript was observed in myostatin knockout mice. In addition, we found increased expression of coding and non-coding genes (Dlk1, Gtl2, Rtl1/Rtl1as, and Rian) at the Dlk1-Dio3 locus in myostatin-deficient skeletal muscle. Moreover, epigenetic changes, associated with the regulation of the Dlk1-Dio3 locus, were observed in myostatin knockout mice. Taken together, this is the first report demonstrating the role of myostatin in regulating the Dlk1-Dio3 (the callipyge) locus in the skeletal muscle. PMID:27992376

Myostatin-deficiency in mice increases global gene expression at the Dlk1-Dio3 locus in the skeletal muscle.

PubMed

Hitachi, Keisuke; Tsuchida, Kunihiro

2017-01-24

Myostatin, a member of the transforming growth factor-beta superfamily, is a negative regulator of skeletal muscle growth and development. Myostatin inhibition leads to increased skeletal muscle mass in mammals; hence, myostatin is considered a potential therapeutic target for skeletal muscle wasting. However, downstream molecules of myostatin in the skeletal muscle have not been fully elucidated. Here, we identified the Dlk1-Dio3 locus at the mouse chromosome 12qF1, also called as the callipyge locus in sheep, as a novel downstream target of myostatin. In skeletal muscle of myostatin knockout mice, the expression of mature miRNAs at the Dlk1-Dio3 locus was significantly increased. The increased miRNA levels are caused by the transcriptional activation of the Dlk1-Dio3 locus, because a significant increase in the primary miRNA transcript was observed in myostatin knockout mice. In addition, we found increased expression of coding and non-coding genes (Dlk1, Gtl2, Rtl1/Rtl1as, and Rian) at the Dlk1-Dio3 locus in myostatin-deficient skeletal muscle. Moreover, epigenetic changes, associated with the regulation of the Dlk1-Dio3 locus, were observed in myostatin knockout mice. Taken together, this is the first report demonstrating the role of myostatin in regulating the Dlk1-Dio3 (the callipyge) locus in the skeletal muscle.

The Impact of Prenatal Parental Locus of Control on Children's Psychological Outcomes in Infancy and Early Childhood: A Prospective 5 Year Study

PubMed Central

Nowicki, Stephen; Iles-Caven, Yasmin; Gregory, Steven; Ellis, Genette; Golding, Jean

2017-01-01

Locus of control is one of the most widely studied concepts in the history of personality psychology. In spite of its popularity and its associations with numerous relevant outcomes, the ability of locus of control to predict future behaviors involving parenting effectiveness has been under researched. The few parent locus of control children's outcome studies are characterized by cross-sectional methodologies that focus on mothers. The present study uses a prospective methodology to compare data on mothers' and fathers' locus of control with their child's behavior outcomes from a large scale research project, the Avon Longitudinal Study of Parents and Children (ALSPAC). Based on Rotter's Social Learning Theory published in 1954 and past empirical research, it was predicted and found that parent internality was associated with more positive child outcomes than parent externality. More specifically, when both parents were internal, their children had more positive outcomes in sleeping, eating, and tantrum behavior as compared to any other parent locus of control combination. However external parents had a less restrictive attitude which appeared to have a more beneficial effect on picky eating. Results confirmed how important parent locus of control is in the lives of children. Based on the findings, researchers are urged to develop interventions to change advice to parents and promote more internal locus of control among parents. PMID:28446887

Effectiveness of teaching cognitive-behavioral techniques on locus of control in hemodialysis patients.

PubMed

Mehrtak, Mohammad; Habibzadeh, Shahram; Farzaneh, Esmaeil; Rjaei-Khiavi, Abdollah

2017-10-01

Many of the cognitive behavioral models and therapeutic protocols developed so far for psychological disorders and chronic diseases have proved effective through clinical research. This study aimed to determine the effectiveness of teaching cognitive-behavioral techniques on locus of control in hemodialysis patients. This controlled clinical trial study was conducted in 2015 with 76 patients selected by census and treated with a hemodialysis machine in the dialysis department of Vali-Asr Hospital in the city of Meshkinshahr. A total of four patients were excluded because of their critical conditions while the rest, who were recruited, were randomly divided into two equal groups of 36 patients as the intervention and control groups. First, the locus of control was measured in both groups through a pretest, and cognitive-behavioral techniques were then taught to the intervention group during eight 45 to 90-minute sessions. The locus of control in patients of both groups was finally re-measured through a posttest. Data were collected using Rotter's Locus of Control Inventory. The Wilcoxon test and Mann-Whitney U test were respectively used in SPSS18 for data analysis. In the pretest and posttest stages respectively, 4.8% and 14.3% of samples in the control group as well as 14.3% and 33.3% of samples in the intervention group enjoyed internal locus of control. The difference between the pretest and posttest scores of internal locus of control in the intervention group was significant (p=0.004), which indicates the positive effect of cognitive-behavioral psychotherapeutic intervention on internalization of locus of control in this group. Given the external locus of control in most of the study patients and also the positive significant effect of cognitive-behavioral psychotherapy on internalization of locus of control in this group of patients, it appears necessary to have a psychology resident present in the hemodialysis department to teach the necessary cognitive-behavioral techniques to internalize the locus of control. The trial was registered at the Thai Clinical Trial Registry (http://www.clinicaltrials.in.th) with the TCTID: TCTR20170707003. The authors received no financial support for the research, authorship, and/or publication of this article.

Asteroseismology with FRESIP: A meter class space telescope

NASA Technical Reports Server (NTRS)

Milford, Peter

1994-01-01

The requirements for asteroseismology and searching for occulting inner planets are similar. The FRESIP mission will be suited to making asteroseismology measurements. Recommendation: Use 30-60 second integrations from one or more CCD's in the FRESIP mosaic, sampled continuously for the entire mission to measure stellar non-radial oscillations with amplitudes of parts per million and frequencies of 0.1 to 10 MHz. These measurements lead to determination of stellar interior helium abundances, rotation rates, depth of convection zones and measuring stellar cycle frequency changes for a variety of stellar types, enabling major advances in stellar structure and evolutionary theories.

Second Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, volume 1

NASA Technical Reports Server (NTRS)

Giampapa, M. S. (Editor); Golub, L. (Editor)

1981-01-01

Solar and stellar atmospheric phenomena and their fundamental physical properties such as gravity, effective temperature and rotation rate, which provides the range in parameter space required to test various theoretical models were investigated. The similarity between solar activity and stellar activity is documented. Some of the topics discussed are: atmospheric structure, magnetic fields, solar and stellar activity, and evolution.

AME - Asteroseismology Made Easy. Estimating stellar properties by using scaled models

NASA Astrophysics Data System (ADS)

Lundkvist, Mia; Kjeldsen, Hans; Silva Aguirre, Victor

2014-06-01

Context. Stellar properties and, in particular stellar radii of exoplanet host stars, are essential for measuring the properties of exoplanets, therefore it is becoming increasingly important to be able to supply reliable stellar radii fast. Grid-modelling is an obvious choice for this, but that only offers a low degree of transparency to non-specialists. Aims: Here we present a new, easy, fast, and transparent method of obtaining stellar properties for stars exhibiting solar-like oscillations. The method, called Asteroseismology Made Easy (AME), can determine stellar masses, mean densities, radii, and surface gravities, as well as estimate ages. We present AME as a visual and powerful tool that could be useful, in particular, in light of the large number of exoplanets being found. Methods: AME consists of a set of figures from which the stellar parameters can be deduced. These figures are made from a grid of stellar evolutionary models that cover masses ranging from 0.7 M⊙ to 1.6 M⊙ in steps of 0.1 M⊙ and metallicities in the interval -0.3 dex ≤ [Fe/H] ≤ +0.3 dex in increments of 0.1 dex. The stellar evolutionary models are computed using the Modules for Experiments in Stellar Astrophysics (MESA) code with simple input physics. Results: We have compared the results from AME with results for three groups of stars: stars with radii determined from interferometry (and measured parallaxes), stars with radii determined from measurements of their parallaxes (and calculated angular diameters), and stars with results based on modelling their individual oscillation frequencies. We find that a comparison of the radii from interferometry to those from AME yields a weighted mean of the fractional differences of just 2%. This is also the level of deviation that we find when we compare the parallax-based radii to the radii determined from AME. Conclusions: The comparison between independently determined stellar parameters and those found using AME show that our method can provide reliable stellar masses, radii, and ages, with median uncertainties in the order of 4%, 2%, and 25%, respectively. http://sac.au.dk/scientific-data/ame

SPIDER. V. MEASURING SYSTEMATIC EFFECTS IN EARLY-TYPE GALAXY STELLAR MASSES FROM PHOTOMETRIC SPECTRAL ENERGY DISTRIBUTION FITTING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swindle, R.; Gal, R. R.; La Barbera, F.

2011-10-15

We present robust statistical estimates of the accuracy of early-type galaxy stellar masses derived from spectral energy distribution (SED) fitting as functions of various empirical and theoretical assumptions. Using large samples consisting of {approx}40,000 galaxies from the Sloan Digital Sky Survey (SDSS; ugriz), of which {approx}5000 are also in the UKIRT Infrared Deep Sky Survey (YJHK), with spectroscopic redshifts in the range 0.05 {<=} z {<=} 0.095, we test the reliability of some commonly used stellar population models and extinction laws for computing stellar masses. Spectroscopic ages (t), metallicities (Z), and extinctions (A{sub V} ) are also computed from fitsmore » to SDSS spectra using various population models. These external constraints are used in additional tests to estimate the systematic errors in the stellar masses derived from SED fitting, where t, Z, and A{sub V} are typically left as free parameters. We find reasonable agreement in mass estimates among stellar population models, with variation of the initial mass function and extinction law yielding systematic biases on the mass of nearly a factor of two, in agreement with other studies. Removing the near-infrared bands changes the statistical bias in mass by only {approx}0.06 dex, adding uncertainties of {approx}0.1 dex at the 95% CL. In contrast, we find that removing an ultraviolet band is more critical, introducing 2{sigma} uncertainties of {approx}0.15 dex. Finally, we find that the stellar masses are less affected by the absence of metallicity and/or dust extinction knowledge. However, there is a definite systematic offset in the mass estimate when the stellar population age is unknown, up to a factor of 2.5 for very old (12 Gyr) stellar populations. We present the stellar masses for our sample, corrected for the measured systematic biases due to photometrically determined ages, finding that age errors produce lower stellar masses by {approx}0.15 dex, with errors of {approx}0.02 dex at the 95% CL for the median stellar age subsample.« less

Work stress and emotional exhaustion in nurses: the mediating role of internal locus of control.

PubMed

Partlak Günüşen, Neslihan; Ustün, Besti; Erdem, Sabri

2014-01-01

Burnout is a major problem for nursing. There is a strong relationship between work stress and emotional exhaustion. Although studies report a negative correlation between the internal locus of control and emotional exhaustion and work stress, the number of studies available on the subject is limited. This study intends to examine the extent to which the relationship between work stress and emotional exhaustion is mediated by nurses' internal locus of control. The study adopted a cross-sectional survey design. The data were analyzed using structural equation modeling techniques. The study sample consisted of 347 nurses who worked in a university hospital in Izmir, Turkey and who agreed to participate in the study. The Work-Related Strain Inventory was used to evaluate the nurses' work stress level, Maslach Burnout Inventory was used to evaluate their emotional exhaustion levels, and the Locus of Control Scale was used to evaluate the internal locus of control. The variables of the study were based on the Neuman Systems Model. Work stress was positively related to internal locus of control (β3 = .21, p < .001), which was, in turn, negatively associated with emotional exhaustion (β = -.03, p > 0.1). Internal locus of control was negatively related to emotional exhaustion (β = -.14, p < .001). Work stress is directly (β = .87, p < .001) and indirectly related to emotional exhaustion (mediated by internal locus of control β = .84, p < .001). Work stress is directly (β = .87, p < .001) and indirectly related to emotional exhaustion (mediated by internal locus of control, β = .84, p < .001). Although the relationship between emotional exhaustion and work stress was mediated, the impact of internal locus of control was limited. It is recommended that different variables be included in future studies so that they can mediate the relationship between work stress and emotional exhaustion.

Inferring mechanisms of copy number change from haplotype structures at the human DEFA1A3 locus.

PubMed

Black, Holly A; Khan, Fayeza F; Tyson, Jess; Al Armour, John

2014-07-21

The determination of structural haplotypes at copy number variable regions can indicate the mechanisms responsible for changes in copy number, as well as explain the relationship between gene copy number and expression. However, obtaining spatial information at regions displaying extensive copy number variation, such as the DEFA1A3 locus, is complex, because of the difficulty in the phasing and assembly of these regions. The DEFA1A3 locus is intriguing in that it falls within a region of high linkage disequilibrium, despite its high variability in copy number (n = 3-16); hence, the mechanisms responsible for changes in copy number at this locus are unclear. In this study, a region flanking the DEFA1A3 locus was sequenced across 120 independent haplotypes with European ancestry, identifying five common classes of DEFA1A3 haplotype. Assigning DEFA1A3 class to haplotypes within the 1000 Genomes project highlights a significant difference in DEFA1A3 class frequencies between populations with different ancestry. The features of each DEFA1A3 class, for example, the associated DEFA1A3 copy numbers, were initially assessed in a European cohort (n = 599) and replicated in the 1000 Genomes samples, showing within-class similarity, but between-class and between-population differences in the features of the DEFA1A3 locus. Emulsion haplotype fusion-PCR was used to generate 61 structural haplotypes at the DEFA1A3 locus, showing a high within-class similarity in structure. Structural haplotypes across the DEFA1A3 locus indicate that intra-allelic rearrangement is the predominant mechanism responsible for changes in DEFA1A3 copy number, explaining the conservation of linkage disequilibrium across the locus. The identification of common structural haplotypes at the DEFA1A3 locus could aid studies into how DEFA1A3 copy number influences expression, which is currently unclear.

The outskirts of spiral galaxies: touching stellar halos at z˜0 and z˜1

NASA Astrophysics Data System (ADS)

Bakos, J.; Trujillo, I.

Taking advantage of ultra-deep imaging of SDSS Stripe82 and the Hubble Ultra Deep Field by HST, we explore the properties of stellar halos at two relevant epochs of cosmic history. At z˜0 we find that the radial surface brightness profiles of disks have a smooth continuation into the stellar halo that starts to affect the surface brightness profiles at mu r'˜28 {mag arcsec-2}, and at a radial distance of gtrsim 4-10 inner scale-lengths. The light contribution of the stellar halo to the total galaxy light varies from ˜1% to ˜5%, but in case of ongoing mergers, the halo light fraction can be as high as ˜10%. The integrated (g'-r') color of the stellar halo of our galaxies range from ˜0.4 to ˜1.2. By confronting these colors with model predictions, these halos can be attributed to moderately aged and metal-poor populations, however the extreme red colors (˜1) cannot be explained by populations of conventional IMFs. Very red halo colors can be attributed to stellar populations dominated by very low mass stars of low to intermediate metallicity produced by bottom-heavy IMFs. At z˜1 stellar halos appear to be ˜2 magnitudes brighter than their local counterparts, meanwhile they exhibit bluer colors ((g'-r')≲0.3 mag), as well. The stellar populations corresponding to these colors are compatible with having ages ≲1 Gyr. This latter observation strongly suggests the possibility that these halos were formed between z˜1 and z˜2. This result matches very well the theoretical predictions that locate most of the formation of the stellar halos at those early epochs. A pure passive evolutionary scenario, where the stellar populations of our high-z haloes simply fade to match the stellar halo properties found in the local universe, is consistent with our data.

Diagnosing the locus of trust: A temporal perspective for trustor, trustee, and dyadic influences on perceived trustworthiness.

PubMed

Jones, Stephen L; Shah, Priti Pradhan

2016-03-01

Extant trust research champions 3 different centers of action that determine perceptions of trust: the trustor (the individual rendering trust judgments), the trustee (the party being trusted), and the trustor-trustee dyad. We refer to the centers of action as loci of trust. Thus far, researchers have investigated determinants residing within each locus independently but have not concurrently investigated all 3 loci. Thus, the relative influence of each locus on perceptions of trust is unknown. Nor is it known how the influence of each locus changes with time. Where is the dominant locus of trust? And how does it change over time? We address these questions by examining the influence of trustors, trustees, and dyads on perceived ability, benevolence, and integrity. We find that trustor influence decreases over time while trustee and dyadic influences increase. We also find that the trustor is the dominant locus for perceived ability, benevolence, and integrity initially, but over time the trustee becomes the dominant locus for perceived ability and integrity. For perceived benevolence, the trustor remains the dominant driver over time. (c) 2016 APA, all rights reserved).

Neurolinguistic programming training, trait anxiety, and locus of control.

PubMed

Konefal, J; Duncan, R C; Reese, M A

1992-06-01

Training in the neurolinguistic programming techniques of shifting perceptual position, visual-kinesthetic dissociation, timelines, and change-history, all based on experiential cognitive processing of remembered events, leads to an increased awareness of behavioral contingencies and a more sensitive recognition of environmental cues which could serve to lower trait anxiety and increase the sense of internal control. This study reports on within-person and between-group changes in trait anxiety and locus of control as measured on the Spielberger State-Trait Anxiety Inventory and Wallston, Wallston, and DeVallis' Multiple Health Locus of Control immediately following a 21-day residential training in neurolinguistic programming. Significant with-in-person decreases in trait-anxiety scores and increases in internal locus of control scores were observed as predicted. Chance and powerful other locus of control scores were unchanged. Significant differences were noted on trait anxiety and locus of control scores between European and U.S. participants, although change scores were similar for the two groups. These findings are consistent with the hypothesis that this training may lower trait-anxiety scores and increase internal locus of control scores. A matched control group was not available, and follow-up was unfortunately not possible.

Content and organization of the human Ig VH locus: definition of three new VH families and linkage to the Ig CH locus.

PubMed Central

Berman, J E; Mellis, S J; Pollock, R; Smith, C L; Suh, H; Heinke, B; Kowal, C; Surti, U; Chess, L; Cantor, C R

1988-01-01

We present a detailed analysis of the content and organization of the human immunoglobulin VH locus. Human VH genes representing five distinct families were isolated, including novel members belonging to two out of three of the known VH gene families (VH1 and VH3) as well as members of three new families (VH4, VH5, and VH6). We report the nucleotide sequence of 21 novel human VH genes, many of which belong to the three new VH gene families. In addition, we provide a preliminary analysis of the organization of these gene segments over the full extent of the locus. We find that the five multi-segment families (VH1-5) have members interspersed over nearly the full 1500-2000 kb of the VH locus, and estimate that the entire heavy chain locus covers 2500 kb or less. Finally, we provide the first report of the physical linkage of the variable and constant loci of a human Ig gene family by demonstrating that the most proximal known human VH segments lie within 100 kb of the constant region locus. Images PMID:3396540

When the Jeans Do Not Fit: How Stellar Feedback Drives Stellar Kinematics and Complicates Dynamical Modeling in Low-mass Galaxies

DOE Office of Scientific and Technical Information (OSTI.GOV)

El-Badry, Kareem; Quataert, Eliot; Wetzel, Andrew R.

In low-mass galaxies, stellar feedback can drive gas outflows that generate non-equilibrium fluctuations in the gravitational potential. Using cosmological zoom-in baryonic simulations from the Feedback in Realistic Environments project, we investigate how these fluctuations affect stellar kinematics and the reliability of Jeans dynamical modeling in low-mass galaxies. We find that stellar velocity dispersion and anisotropy profiles fluctuate significantly over the course of galaxies’ starburst cycles. We therefore predict an observable correlation between star formation rate and stellar kinematics: dwarf galaxies with higher recent star formation rates should have systemically higher stellar velocity dispersions. This prediction provides an observational test ofmore » the role of stellar feedback in regulating both stellar and dark-matter densities in dwarf galaxies. We find that Jeans modeling, which treats galaxies as virialized systems in dynamical equilibrium, overestimates a galaxy’s dynamical mass during periods of post-starburst gas outflow and underestimates it during periods of net inflow. Short-timescale potential fluctuations lead to typical errors of ∼20% in dynamical mass estimates, even if full three-dimensional stellar kinematics—including the orbital anisotropy—are known exactly. When orbital anisotropy is not known a priori, typical mass errors arising from non-equilibrium fluctuations in the potential are larger than those arising from the mass-anisotropy degeneracy. However, Jeans modeling alone cannot reliably constrain the orbital anisotropy, and problematically, it often favors anisotropy models that do not reflect the true profile. If galaxies completely lose their gas and cease forming stars, fluctuations in the potential subside, and Jeans modeling becomes much more reliable.« less

Influence of stellar multiplicity on planet formation. II. Planets are less common in multiple-star systems with separations smaller than 1500 AU

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Ji; Fischer, Debra A.; Xie, Ji-Wei

2014-08-20

Almost half of the stellar systems in the solar neighborhood are made up of multiple stars. In multiple-star systems, planet formation is under the dynamical influence of stellar companions, and the planet occurrence rate is expected to be different from that of single stars. There have been numerous studies on the planet occurrence rate of single star systems. However, to fully understand planet formation, the planet occurrence rate in multiple-star systems needs to be addressed. In this work, we infer the planet occurrence rate in multiple-star systems by measuring the stellar multiplicity rate for planet host stars. For a subsamplemore » of 56 Kepler planet host stars, we use adaptive optics (AO) imaging and the radial velocity (RV) technique to search for stellar companions. The combination of these two techniques results in high search completeness for stellar companions. We detect 59 visual stellar companions to 25 planet host stars with AO data. Three stellar companions are within 2'' and 27 within 6''. We also detect two possible stellar companions (KOI 5 and KOI 69) showing long-term RV acceleration. After correcting for a bias against planet detection in multiple-star systems due to flux contamination, we find that planet formation is suppressed in multiple-star systems with separations smaller than 1500 AU. Specifically, we find that compared to single star systems, planets in multiple-star systems occur 4.5 ± 3.2, 2.6 ± 1.0, and 1.7 ± 0.5 times less frequently when a stellar companion is present at a distance of 10, 100, and 1000 AU, respectively. This conclusion applies only to circumstellar planets; the planet occurrence rate for circumbinary planets requires further investigation.« less

The universal relation of galactic chemical evolution: the origin of the mass-metallicity relation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zahid, H. Jabran; Dima, Gabriel I.; Kudritzki, Rolf-Peter

2014-08-20

We examine the mass-metallicity relation for z ≲ 1.6. The mass-metallicity relation follows a steep slope with a turnover, or 'knee', at stellar masses around 10{sup 10} M {sub ☉}. At stellar masses higher than the characteristic turnover mass, the mass-metallicity relation flattens as metallicities begin to saturate. We show that the redshift evolution of the mass-metallicity relation depends only on the evolution of the characteristic turnover mass. The relationship between metallicity and the stellar mass normalized to the characteristic turnover mass is independent of redshift. We find that the redshift-independent slope of the mass-metallicity relation is set by themore » slope of the relationship between gas mass and stellar mass. The turnover in the mass-metallicity relation occurs when the gas-phase oxygen abundance is high enough that the amount of oxygen locked up in low-mass stars is an appreciable fraction of the amount of oxygen produced by massive stars. The characteristic turnover mass is the stellar mass, where the stellar-to-gas mass ratio is unity. Numerical modeling suggests that the relationship between metallicity and the stellar-to-gas mass ratio is a redshift-independent, universal relationship followed by all galaxies as they evolve. The mass-metallicity relation originates from this more fundamental universal relationship between metallicity and the stellar-to-gas mass ratio. We test the validity of this universal metallicity relation in local galaxies where stellar mass, metallicity, and gas mass measurements are available. The data are consistent with a universal metallicity relation. We derive an equation for estimating the hydrogen gas mass from measurements of stellar mass and metallicity valid for z ≲ 1.6 and predict the cosmological evolution of galactic gas masses.« less

Developmental regulation of DNA replication timing at the human beta globin locus.

PubMed

Simon, I; Tenzen, T; Mostoslavsky, R; Fibach, E; Lande, L; Milot, E; Gribnau, J; Grosveld, F; Fraser, P; Cedar, H

2001-11-01

The human beta globin locus replicates late in most cell types, but becomes early replicating in erythroid cells. Using FISH to map DNA replication timing around the endogenous beta globin locus and by applying a genetic approach in transgenic mice, we have demonstrated that both the late and early replication states are controlled by regulatory elements within the locus control region. These results also show that the pattern of replication timing is set up by mechanisms that work independently of gene transcription.

VizieR Online Data Catalog: Properties of OB associations in IC 1613 (Garcia+, 2010)

NASA Astrophysics Data System (ADS)

Garcia, M.; Herrero, A.; Castro, N.; Corral, L.; Rosenberg, A.

2014-06-01

To understand the structure and evolution of massive stars, systematic surveys of the Local Group galaxies have been undertaken, to find these objects in environments of different chemical abundances. We focus on the metal-poor irregular galaxy IC 1613 to analyze the stellar and wind structure of its low-metallicity massive stars. We ultimately aim to study the metallicity-dependent driving mechanism of the winds of blue massive stars and use metal-poor massive stars of the Local Volume as a proxy for the stars in the early Universe. In a previous paper we produced a list of OB associations in IC 1613. Their properties are not only a powerful aid towards finding the most interesting candidate massive stars, but also reveal the structure and recent star formation history of the galaxy. We characterize these OB associations and study their connection with the galactic global properties. The reddening-free Q parameter is a powerful tool in the photometric analysis of young populations of massive stars, since it exhibits a smaller degree of degeneracy with OB spectral types than the B-V color. The color-magnitude diagram (Q vs. V) of the OB associations in IC 1613 is studied to determine their age and mass, and confirm the population of young massive stars. We identified more than 10 stars with M>=50M⊙. Spectral classification available for some of them confirm their massive nature, yet we find the common discrepancy with the spectroscopically derived masses. There is a general increasing trend of the mass of the most massive member with the number of members of each association, but not with the stellar density. The average diameter of the associations of this catalog is 40pc, half the historically considered typical size of OB associations. Size increases with the association population. The distribution of the groups strongly correlates with that of neutral and ionized hydrogen. We find the largest dispersion of association ages in the bubble region of the galaxy where hydrogen is abundant, implying that recent star formation has proceeded over a longer period of time than in the rest of the galaxy, and is still ongoing. Very young associations are found at the west of the galaxy far from the bubble region, traditionally considered the sole locus of star formation, but still rich in neutral hydrogen. The contrast in the stellar properties derived from photometry and spectroscopy (when the latter is available) shows that the Q pseudo-color is very useful for estimating the parameters of OB stars when only photometric observations exist. This work helped define an extensive pool of candidate OB stars for subsequent spectroscopic analyses designed to study the structure and winds of metal-poor massive stars. (2 data files).

Advancing the understanding of plasma transport in mid-size stellarators

NASA Astrophysics Data System (ADS)

Hidalgo, Carlos; Talmadge, Joseph; Ramisch, Mirko; TJ-II, the; HXS; TJ-K Teams

2017-01-01

The tokamak and the stellarator are the two main candidate concepts for magnetically confining fusion plasmas. The flexibility of the mid-size stellarator devices together with their unique diagnostic capabilities make them ideally suited to study the relation between magnetic topology, electric fields and transport. This paper addresses advances in the understanding of plasma transport in mid-size stellarators with an emphasis on the physics of flows, transport control, impurity and particle transport and fast particles. The results described here emphasize an improved physics understanding of phenomena in stellarators that complements the empirical approach. Experiments in mid-size stellarators support the development of advanced plasma scenarios in Wendelstein 7-X (W7-X) and, in concert with better physics understanding in tokamaks, may ultimately lead to an advance in the prediction of burning plasma behaviour.

Dynamical effects of stellar companions

NASA Astrophysics Data System (ADS)

Naoz, Smadar

2015-08-01

The fraction of stellar binaries in the field is extremely high (about 40% - 70% for > 1 Msun stars), and thus, given this frequency, a large fraction of all exoplanetary systems may reside in binaries. While close-in giant planets tend to be found preferentially in binary stellar systems it seems that the frequency of giant planets in close binaries (<100 AU) is significantly lower than in the overall population. Stellar companions’ gravitational perturbations may significantly alter the planetary orbits around their partner on secular timescales. They can drive planets to large eccentric orbits which can either result in plunging these planets into the star or shrinking their orbits and forming short period planets. I will review the dynamical effects stellar binaries have on a planetary systems. I will also present new results on the influence that stellar evolution has on the dynamical processes in these systems.

The Sun as a variable star: Solar and stellar irradiance variations; Colloquium of the International Astronomical Union, 143rd, Boulder, CO, Jun. 20-25, 1993

NASA Technical Reports Server (NTRS)

Pap, Judit M. (Editor); Froehlich, Claus (Editor); Hudson, Hugh S. (Editor); Tobiska, W. Kent (Editor)

1994-01-01

Variations in solar and stellar irradiances have long been of interest. An International Astronomical Union (IAU) colloquium reviewed such relevant subjects as observations, theoretical interpretations, and empirical and physical models, with a special emphasis on climatic impact of solar irradiance variability. Specific topics discussed included: (1) General Reviews on Observations of Solar and Stellar Irradiance Variability; (2) Observational Programs for Solar and Stellar Irradiance Variability; (3) Variability of Solar and Stellar Irradiance Related to the Network, Active Regions (Sunspots and Plages), and Large-Scale Magnetic Structures; (4) Empirical Models of Solar Total and Spectral Irradiance Variability; (5) Solar and Stellar Oscillations, Irradiance Variations and their Interpretations; and (6) The Response of the Earth's Atmosphere to Solar Irradiance Variations and Sun-Climate Connections.

Two chemically similar stellar overdensities on opposite sides of the plane of the Galactic disk.

PubMed

Bergemann, Maria; Sesar, Branimir; Cohen, Judith G; Serenelli, Aldo M; Sheffield, Allyson; Li, Ting S; Casagrande, Luca; Johnston, Kathryn V; Laporte, Chervin F P; Price-Whelan, Adrian M; Schönrich, Ralph; Gould, Andrew

2018-03-15

Our Galaxy is thought to have an active evolutionary history, dominated over the past ten billion years or so by star formation, the accretion of cold gas and, in particular, the merging of clumps of baryonic and dark matter. The stellar halo-the faint, roughly spherical component of the Galaxy-reveals rich 'fossil' evidence of these interactions, in the form of stellar streams, substructures and chemically distinct stellar components. The effects of interactions with dwarf galaxies on the content and morphology of the Galactic disk are still being explored. Recent studies have identified kinematically distinct stellar substructures and moving groups of stars in our Galaxy, which may have extragalactic origins. There is also mounting evidence that stellar overdensities (regions with greater-than-average stellar density) at the interface between the outer disk and the halo could have been caused by the interaction of a dwarf galaxy with the disk. Here we report a spectroscopic analysis of 14 stars from two stellar overdensities, each lying about five kiloparsecs above or below the Galactic plane-locations suggestive of an association with the stellar halo. We find that the chemical compositions of these two groups of stars are almost identical, both within and between these overdensities, and closely match the abundance patterns of stars in the Galactic disk. We conclude that these stars came from the disk, and that the overdensities that they are part of were created by tidal interactions of the disk with passing or merging dwarf galaxies.

Two chemically similar stellar overdensities on opposite sides of the plane of the Galactic disk

NASA Astrophysics Data System (ADS)

Bergemann, Maria; Sesar, Branimir; Cohen, Judith G.; Serenelli, Aldo M.; Sheffield, Allyson; Li, Ting S.; Casagrande, Luca; Johnston, Kathryn V.; Laporte, Chervin F. P.; Price-Whelan, Adrian M.; Schönrich, Ralph; Gould, Andrew

2018-03-01

Our Galaxy is thought to have an active evolutionary history, dominated over the past ten billion years or so by star formation, the accretion of cold gas and, in particular, the merging of clumps of baryonic and dark matter. The stellar halo—the faint, roughly spherical component of the Galaxy—reveals rich ‘fossil’ evidence of these interactions, in the form of stellar streams, substructures and chemically distinct stellar components. The effects of interactions with dwarf galaxies on the content and morphology of the Galactic disk are still being explored. Recent studies have identified kinematically distinct stellar substructures and moving groups of stars in our Galaxy, which may have extragalactic origins. There is also mounting evidence that stellar overdensities (regions with greater-than-average stellar density) at the interface between the outer disk and the halo could have been caused by the interaction of a dwarf galaxy with the disk. Here we report a spectroscopic analysis of 14 stars from two stellar overdensities, each lying about five kiloparsecs above or below the Galactic plane—locations suggestive of an association with the stellar halo. We find that the chemical compositions of these two groups of stars are almost identical, both within and between these overdensities, and closely match the abundance patterns of stars in the Galactic disk. We conclude that these stars came from the disk, and that the overdensities that they are part of were created by tidal interactions of the disk with passing or merging dwarf galaxies.

Comparing Dark Energy Survey and HST –CLASH observations of the galaxy cluster RXC J2248.7-4431: implications for stellar mass versus dark matter

DOE PAGES

Palmese, A.; Lahav, O.; Banerji, M.; ...

2016-08-20

We derive the stellar mass fraction in the galaxy cluster RXC J2248.7-4431 observed with the Dark Energy Survey (DES) during the Science Verification period. We compare the stellar mass results from DES (5 filters) with those from the Hubble Space Telescope CLASH (17 filters). When the cluster spectroscopic redshift is assumed, we show that stellar masses from DES can be estimated within 25% of CLASH values. We compute the stellar mass contribution coming from red and blue galaxies, and study the relation between stellar mass and the underlying dark matter using weak lensing studies with DES and CLASH. An analysismore » of the radial profiles of the DES total and stellar mass yields a stellar-to-total fraction of f*=7.0+-2.2x10^-3 within a radius of r_200c~3 Mpc. Our analysis also includes a comparison of photometric redshifts and star/galaxy separation efficiency for both datasets. We conclude that space-based small field imaging can be used to calibrate the galaxy properties in DES for the much wider field of view. The technique developed to derive the stellar mass fraction in galaxy clusters can be applied to the ~100 000 clusters that will be observed within this survey. The stacking of all the DES clusters would reduce the errors on f* estimates and deduce important information about galaxy evolution.« less

The PyCASSO database: spatially resolved stellar population properties for CALIFA galaxies

NASA Astrophysics Data System (ADS)

de Amorim, A. L.; García-Benito, R.; Cid Fernandes, R.; Cortijo-Ferrero, C.; González Delgado, R. M.; Lacerda, E. A. D.; López Fernández, R.; Pérez, E.; Vale Asari, N.

2017-11-01

The Calar Alto Legacy Integral Field Area (CALIFA) survey, a pioneer in integral field spectroscopy legacy projects, has fostered many studies exploring the information encoded on the spatially resolved data on gaseous and stellar features in the optical range of galaxies. We describe a value-added catalogue of stellar population properties for CALIFA galaxies analysed with the spectral synthesis code starlight and processed with the pycasso platform. Our public database (http://pycasso.ufsc.br/, mirror at http://pycasso.iaa.es/) comprises 445 galaxies from the CALIFA Data Release 3 with COMBO data. The catalogue provides maps for the stellar mass surface density, mean stellar ages and metallicities, stellar dust attenuation, star formation rates, and kinematics. Example applications both for individual galaxies and for statistical studies are presented to illustrate the power of this data set. We revisit and update a few of our own results on mass density radial profiles and on the local mass-metallicity relation. We also show how to employ the catalogue for new investigations, and show a pseudo Schmidt-Kennicutt relation entirely made with information extracted from the stellar continuum. Combinations to other databases are also illustrated. Among other results, we find a very good agreement between star formation rate surface densities derived from the stellar continuum and the H α emission. This public catalogue joins the scientific community's effort towards transparency and reproducibility, and will be useful for researchers focusing on (or complementing their studies with) stellar properties of CALIFA galaxies.

Comparing Dark Energy Survey and HST-CLASH observations of the galaxy cluster RXC J2248.7-4431: implications for stellar mass versus dark matter

NASA Astrophysics Data System (ADS)

Palmese, A.; Lahav, O.; Banerji, M.; Gruen, D.; Jouvel, S.; Melchior, P.; Aleksić, J.; Annis, J.; Diehl, H. T.; Hartley, W. G.; Jeltema, T.; Romer, A. K.; Rozo, E.; Rykoff, E. S.; Seitz, S.; Suchyta, E.; Zhang, Y.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Crocce, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Dietrich, J. P.; Doel, P.; Estrada, J.; Evrard, A. E.; Flaugher, B.; Frieman, J.; Gerdes, D. W.; Goldstein, D. A.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Li, T. S.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Miller, C. J.; Miquel, R.; Nord, B.; Ogando, R.; Plazas, A. A.; Roodman, A.; Sanchez, E.; Scarpine, V.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Tucker, D.; Vikram, V.

2016-12-01

We derive the stellar mass fraction in the galaxy cluster RXC J2248.7-4431 observed with the Dark Energy Survey (DES) during the Science Verification period. We compare the stellar mass results from DES (five filters) with those from the Hubble Space Telescope Cluster Lensing And Supernova Survey (CLASH; 17 filters). When the cluster spectroscopic redshift is assumed, we show that stellar masses from DES can be estimated within 25 per cent of CLASH values. We compute the stellar mass contribution coming from red and blue galaxies, and study the relation between stellar mass and the underlying dark matter using weak lensing studies with DES and CLASH. An analysis of the radial profiles of the DES total and stellar mass yields a stellar-to-total fraction of f⋆ = (6.8 ± 1.7) × 10-3 within a radius of r200c ≃ 2 Mpc. Our analysis also includes a comparison of photometric redshifts and star/galaxy separation efficiency for both data sets. We conclude that space-based small field imaging can be used to calibrate the galaxy properties in DES for the much wider field of view. The technique developed to derive the stellar mass fraction in galaxy clusters can be applied to the ˜100 000 clusters that will be observed within this survey and yield important information about galaxy evolution.

Comparing Dark Energy Survey and HST –CLASH observations of the galaxy cluster RXC J2248.7-4431: implications for stellar mass versus dark matter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palmese, A.; Lahav, O.; Banerji, M.

We derive the stellar mass fraction in the galaxy cluster RXC J2248.7-4431 observed with the Dark Energy Survey (DES) during the Science Verification period. We compare the stellar mass results from DES (5 filters) with those from the Hubble Space Telescope CLASH (17 filters). When the cluster spectroscopic redshift is assumed, we show that stellar masses from DES can be estimated within 25% of CLASH values. We compute the stellar mass contribution coming from red and blue galaxies, and study the relation between stellar mass and the underlying dark matter using weak lensing studies with DES and CLASH. An analysismore » of the radial profiles of the DES total and stellar mass yields a stellar-to-total fraction of f*=7.0+-2.2x10^-3 within a radius of r_200c~3 Mpc. Our analysis also includes a comparison of photometric redshifts and star/galaxy separation efficiency for both datasets. We conclude that space-based small field imaging can be used to calibrate the galaxy properties in DES for the much wider field of view. The technique developed to derive the stellar mass fraction in galaxy clusters can be applied to the ~100 000 clusters that will be observed within this survey. The stacking of all the DES clusters would reduce the errors on f* estimates and deduce important information about galaxy evolution.« less

Comparing Dark Energy Survey and HST –CLASH observations of the galaxy cluster RXC J2248.7-4431: implications for stellar mass versus dark matter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palmese, A.; Lahav, O.; Banerji, M.

We derive the stellar mass fraction in the galaxy cluster RXC J2248.7-4431 observed with the Dark Energy Survey (DES) during the Science Verification period. We compare the stellar mass results from DES (five filters) with those from the Hubble Space Telescope Cluster Lensing And Supernova Survey (CLASH; 17 filters). When the cluster spectroscopic redshift is assumed, we show that stellar masses from DES can be estimated within 25 per cent of CLASH values. We compute the stellar mass contribution coming from red and blue galaxies, and study the relation between stellar mass and the underlying dark matter using weak lensingmore » studies with DES and CLASH. An analysis of the radial profiles of the DES total and stellar mass yields a stellar-to-total fraction of f(star) = (6.8 +/- 1.7) x 10(-3) within a radius of r(200c) similar or equal to 2 Mpc. Our analysis also includes a comparison of photometric redshifts and star/galaxy separation efficiency for both data sets. We conclude that space-based small field imaging can be used to calibrate the galaxy properties in DES for the much wider field of view. The technique developed to derive the stellar mass fraction in galaxy clusters can be applied to the similar to 100 000 clusters that will be observed within this survey and yield important information about galaxy evolution.« less

Comparative Genomics of the Ectomycorrhizal Sister Species Rhizopogon vinicolor and Rhizopogon vesiculosus (Basidiomycota: Boletales) Reveals a Divergence of the Mating Type B Locus

PubMed Central

Mujic, Alija Bajro; Kuo, Alan; Tritt, Andrew; Lipzen, Anna; Chen, Cindy; Johnson, Jenifer; Sharma, Aditi; Barry, Kerrie; Grigoriev, Igor V.; Spatafora, Joseph W.

2017-01-01

Divergence of breeding system plays an important role in fungal speciation. Ectomycorrhizal fungi, however, pose a challenge for the study of reproductive biology because most cannot be mated under laboratory conditions. To overcome this barrier, we sequenced the draft genomes of the ectomycorrhizal sister species Rhizopogon vinicolor Smith and Zeller and R. vesiculosus Smith and Zeller (Basidiomycota, Boletales)—the first genomes available for Basidiomycota truffles—and characterized gene content and organization surrounding their mating type loci. Both species possess a pair of homeodomain transcription factor homologs at the mating type A-locus as well as pheromone receptor and pheromone precursor homologs at the mating type B-locus. Comparison of Rhizopogon genomes with genomes from Boletales, Agaricales, and Polyporales revealed synteny of the A-locus region within Boletales, but several genomic rearrangements across orders. Our findings suggest correlation between gene content at the B-locus region and breeding system in Boletales with tetrapolar species possessing more diverse gene content than bipolar species. Rhizopogon vinicolor possesses a greater number of B-locus pheromone receptor and precursor genes than R. vesiculosus, as well as a pair of isoprenyl cysteine methyltransferase genes flanking the B-locus compared to a single copy in R. vesiculosus. Examination of dikaryotic single nucleotide polymorphisms within genomes revealed greater heterozygosity in R. vinicolor, consistent with increased rates of outcrossing. Both species possess the components of a heterothallic breeding system with R. vinicolor possessing a B-locus region structure consistent with tetrapolar Boletales and R. vesiculosus possessing a B-locus region structure intermediate between bipolar and tetrapolar Boletales. PMID:28450370

Physical mapping of a pollen modifier locus controlling self-incompatibility in apricot and synteny analysis within the Rosaceae.

PubMed

Zuriaga, Elena; Molina, Laura; Badenes, María Luisa; Romero, Carlos

2012-06-01

S-locus products (S-RNase and F-box proteins) are essential for the gametophytic self-incompatibility (GSI) specific recognition in Prunus. However, accumulated genetic evidence suggests that other S-locus unlinked factors are also required for GSI. For instance, GSI breakdown was associated with a pollen-part mutation unlinked to the S-locus in the apricot (Prunus armeniaca L.) cv. 'Canino'. Fine-mapping of this mutated modifier gene (M-locus) and the synteny analysis of the M-locus within the Rosaceae are here reported. A segregation distortion loci mapping strategy, based on a selectively genotyped population, was used to map the M-locus. In addition, a bacterial artificial chromosome (BAC) contig was constructed for this region using overlapping oligonucleotides probes, and BAC-end sequences (BES) were blasted against Rosaceae genomes to perform micro-synteny analysis. The M-locus was mapped to the distal part of chr.3 flanked by two SSR markers within an interval of 1.8 cM corresponding to ~364 Kb in the peach (Prunus persica L. Batsch) genome. In the integrated genetic-physical map of this region, BES were mapped against the peach scaffold_3 and BACs were anchored to the apricot map. Micro-syntenic blocks were detected in apple (Malus × domestica Borkh.) LG17/9 and strawberry (Fragaria vesca L.) FG6 chromosomes. The M-locus fine-scale mapping provides a solid basis for self-compatibility marker-assisted selection and for positional cloning of the underlying gene, a necessary goal to elucidate the pollen rejection mechanism in Prunus. In a wider context, the syntenic regions identified in peach, apple and strawberry might be useful to interpret GSI evolution in Rosaceae.

Comparative population genetics of a mimicry locus among hybridizing Heliconius butterfly species.

PubMed

Chamberlain, N L; Hill, R I; Baxter, S W; Jiggins, C D; Kronforst, M R

2011-09-01

The comimetic Heliconius butterfly species pair, H. erato and H. melpomene, appear to use a conserved Mendelian switch locus to generate their matching red wing patterns. Here we investigate whether H. cydno and H. pachinus, species closely related to H. melpomene, use this same switch locus to generate their highly divergent red and brown color pattern elements. Using an F2 intercross between H. cydno and H. pachinus, we first map the genomic positions of two novel red/brown wing pattern elements; the G locus, which controls the presence of red vs brown at the base of the ventral wings, and the Br locus, which controls the presence vs absence of a brown oval pattern on the ventral hind wing. The results reveal that the G locus is tightly linked to markers in the genomic interval that controls red wing pattern elements of H. erato and H. melpomene. Br is on the same linkage group but approximately 26 cM away. Next, we analyze fine-scale patterns of genetic differentiation and linkage disequilibrium throughout the G locus candidate interval in H. cydno, H. pachinus and H. melpomene, and find evidence for elevated differentiation between H. cydno and H. pachinus, but no localized signature of association. Overall, these results indicate that the G locus maps to the same interval as the locus controlling red patterning in H. melpomene and H. erato. This, in turn, suggests that the genes controlling red pattern elements may be homologous across Heliconius, supporting the hypothesis that Heliconius butterflies use a limited suite of conserved genetic switch loci to generate both convergent and divergent wing patterns.

The association of genetic variants of type 2 diabetes with kidney function.

PubMed

Franceschini, Nora; Shara, Nawar M; Wang, Hong; Voruganti, V Saroja; Laston, Sandy; Haack, Karin; Lee, Elisa T; Best, Lyle G; Maccluer, Jean W; Cochran, Barbara J; Dyer, Thomas D; Howard, Barbara V; Cole, Shelley A; North, Kari E; Umans, Jason G

2012-07-01

Type 2 diabetes is highly prevalent and is the major cause of progressive chronic kidney disease in American Indians. Genome-wide association studies identified several loci associated with diabetes but their impact on susceptibility to diabetic complications is unknown. We studied the association of 18 type 2 diabetes genome-wide association single-nucleotide polymorphisms (SNPs) with estimated glomerular filtration rate (eGFR; MDRD equation) and urine albumin-to-creatinine ratio in 6958 Strong Heart Study family and cohort participants. Center-specific residuals of eGFR and log urine albumin-to-creatinine ratio, obtained from linear regression models adjusted for age, sex, and body mass index, were regressed onto SNP dosage using variance component models in family data and linear regression in unrelated individuals. Estimates were then combined across centers. Four diabetic loci were associated with eGFR and one locus with urine albumin-to-creatinine ratio. A SNP in the WFS1 gene (rs10010131) was associated with higher eGFR in younger individuals and with increased albuminuria. SNPs in the FTO, KCNJ11, and TCF7L2 genes were associated with lower eGFR, but not albuminuria, and were not significant in prospective analyses. Our findings suggest a shared genetic risk for type 2 diabetes and its kidney complications, and a potential role for WFS1 in early-onset diabetic nephropathy in American Indian populations.

Multidimensional profiles of health locus of control in Hispanic Americans.

PubMed

Champagne, Brian R; Fox, Rina S; Mills, Sarah D; Sadler, Georgia Robins; Malcarne, Vanessa L

2016-10-01

Latent profile analysis identified health locus of control profiles among 436 Hispanic Americans who completed the Multidimensional Health Locus of Control scales. Results revealed four profiles: Internally Oriented-Weak, -Moderate, -Strong, and Externally Oriented. The profile groups were compared on sociocultural and demographic characteristics, health beliefs and behaviors, and physical and mental health outcomes. The Internally Oriented-Strong group had less cancer fatalism, religiosity, and equity health attributions, and more alcohol consumption than the other three groups; the Externally Oriented group had stronger equity health attributions and less alcohol consumption. Deriving multidimensional health locus of control profiles through latent profile analysis allows examination of the relationships of health locus of control subtypes to health variables. © The Author(s) 2015.

SP_Ace: Stellar Parameters And Chemical abundances Estimator

NASA Astrophysics Data System (ADS)

Boeche, C.; Grebel, E. K.

2018-05-01

SP_Ace (Stellar Parameters And Chemical abundances Estimator) estimates the stellar parameters Teff, log g, [M/H], and elemental abundances. It employs 1D stellar atmosphere models in Local Thermodynamic Equilibrium (LTE). The code is highly automated and suitable for analyzing the spectra of large spectroscopic surveys with low or medium spectral resolution (R = 2000-20 000). A web service for calculating these values with the software is also available.

Testing stellar evolution models with detached eclipsing binaries

NASA Astrophysics Data System (ADS)

Higl, J.; Weiss, A.

2017-12-01

Stellar evolution codes, as all other numerical tools, need to be verified. One of the standard stellar objects that allow stringent tests of stellar evolution theory and models, are detached eclipsing binaries. We have used 19 such objects to test our stellar evolution code, in order to see whether standard methods and assumptions suffice to reproduce the observed global properties. In this paper we concentrate on three effects that contain a specific uncertainty: atomic diffusion as used for standard solar model calculations, overshooting from convective regions, and a simple model for the effect of stellar spots on stellar radius, which is one of the possible solutions for the radius problem of M dwarfs. We find that in general old systems need diffusion to allow for, or at least improve, an acceptable fit, and that systems with convective cores indeed need overshooting. Only one system (AI Phe) requires the absence of it for a successful fit. To match stellar radii for very low-mass stars, the spot model proved to be an effective approach, but depending on model details, requires a high percentage of the surface being covered by spots. We briefly discuss improvements needed to further reduce the freedom in modelling and to allow an even more restrictive test by using these objects.

Binary Population and Spectral Synthesis Version 2.1: Construction, Observational Verification, and New Results

NASA Astrophysics Data System (ADS)

Eldridge, J. J.; Stanway, E. R.; Xiao, L.; McClelland, L. A. S.; Taylor, G.; Ng, M.; Greis, S. M. L.; Bray, J. C.

2017-11-01

The Binary Population and Spectral Synthesis suite of binary stellar evolution models and synthetic stellar populations provides a framework for the physically motivated analysis of both the integrated light from distant stellar populations and the detailed properties of those nearby. We present a new version 2.1 data release of these models, detailing the methodology by which Binary Population and Spectral Synthesis incorporates binary mass transfer and its effect on stellar evolution pathways, as well as the construction of simple stellar populations. We demonstrate key tests of the latest Binary Population and Spectral Synthesis model suite demonstrating its ability to reproduce the colours and derived properties of resolved stellar populations, including well-constrained eclipsing binaries. We consider observational constraints on the ratio of massive star types and the distribution of stellar remnant masses. We describe the identification of supernova progenitors in our models, and demonstrate a good agreement to the properties of observed progenitors. We also test our models against photometric and spectroscopic observations of unresolved stellar populations, both in the local and distant Universe, finding that binary models provide a self-consistent explanation for observed galaxy properties across a broad redshift range. Finally, we carefully describe the limitations of our models, and areas where we expect to see significant improvement in future versions.

A FEATURE MOVIE OF SiO EMISSION 20-100 AU FROM THE MASSIVE YOUNG STELLAR OBJECT ORION SOURCE I

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matthews, L. D.; Greenhill, L. J.; Goddi, C.

2010-01-01

We present multi-epoch Very Long Baseline Array imaging of the {sup 28}SiO v = 1 and v = 2, J = 1-0 maser emission toward the massive young stellar object (YSO) Orion Source I. Both SiO transitions were observed simultaneously with an angular resolution of approx0.5 mas (approx0.2 AU for d = 414 pc) and a spectral resolution of approx0.2 km s{sup -1}. Here we explore the global properties and kinematics of the emission through two 19-epoch animated movies spanning 21 months (from 2001 March 19 to 2002 December 10). These movies provide the most detailed view to date ofmore » the dynamics and temporal evolution of molecular material within approx20-100 AU of a massive (approx>8 M{sub sun}) YSO. As in previous studies, we find that the bulk of the SiO masers surrounding Source I lie in an X-shaped locus; the emission in the south and east arms is predominantly blueshifted, and emission in the north and west is predominantly redshifted. In addition, bridges of intermediate-velocity emission are observed connecting the red and blue sides of the emission distribution. We have measured proper motions of over 1000 individual maser features and found that these motions are characterized by a combination of radially outward migrations along the four main maser-emitting arms and motions tangent to the intermediate-velocity bridges. We interpret the SiO masers as arising from a wide-angle bipolar wind emanating from a rotating, edge-on disk. The detection of maser features along extended, curved filaments suggests that magnetic fields may play a role in launching and/or shaping the wind. Our observations appear to support a picture in which stars with masses as high as at least 8 M{sub sun} form via disk-mediated accretion. However, we cannot yet rule out that the Source I disk may have been formed or altered following a recent close encounter.« less

Young Low-Mass Stars and Brown Dwarfs in IC 348

NASA Astrophysics Data System (ADS)

Luhman, K. L.

1999-11-01

I present new results from a continuing program to identify and characterize the low-mass stellar and substellar populations in the young cluster IC 348 (0.5-10 Myr). Optical spectroscopy has revealed young objects with spectral types as late as M8.25. The intrinsic J-H and H-K colors of these sources are dwarflike, whereas the R-I and I-J colors appear intermediate between the colors of dwarfs and giants. Furthermore, the spectra from 6500 to 9500 Å are reproduced well with averages of standard dwarf and giant spectra, suggesting that such averages should be used in the classification of young late-type sources. An H-R diagram is constructed for the low-mass population in IC 348 (K6-M8). The presumably coeval components of the young quadruple system GG Tau (White et al.) and the locus of stars in IC 348 are used as empirical isochrones to test the theoretical evolutionary models. The calculations of Burrows et al. do not appear to be consistent with the data at these earliest stages of stellar evolution. There is fair agreement between the data and the model isochrones of D'Antona & Mazzitelli, except near the hydrogen-burning limit. The agreement cannot be improved by changing the conversion between spectral types and effective temperatures. On the other hand, for the models of Baraffe et al., an adjustment of the temperature scale to progressively warmer temperatures at later M types, intermediate between dwarfs and giants, brings all components of GG Tau onto the same model isochrone and gives the population of IC 348 a constant age and age spread as a function of mass. When other observational constraints are considered, such as the dynamical masses of GM Aur, DM Tau, and GG Tau A, the models of Baraffe et al. are the most consistent with observations of young systems. With compatible temperature scales, the models of both D'Antona & Mazzitelli and Baraffe et al. suggest that the hydrogen-burning mass limit occurs near M6 at ages of <~10 Myr. Thus, several likely brown dwarfs are discovered in this study of IC 348, with masses down to ~20-30 MJ.

Locus of Control or Self-Esteem; Which One is the Best Predictor of Academic Achievement in Iranian College Students.

PubMed

Hosseini, Seyyed Nasrollah; Mirzaei Alavijeh, Mehdi; Karami Matin, Behzad; Hamzeh, Behrooz; Ashtarian, Hossein; Jalilian, Farzad

2016-03-01

Self-esteem and behavioral consequences, which are due to external or internal locus of control, are effective on academic achievement of students. The aim of this study was to determine the prediction of locus of control and self-esteem in academic achievement among the students. This cross-sectional study was conducted on 300 college students in Kermanshah University of Medical Sciences in 2014. Data collection tools were in three sections: demographic, Rotter internal-external locus of control scale and Coopersmith self-esteem inventory. Data were analyzed using the SPSS software version 21. Results showed that 29.8% and 76.2% of the participants had internal locus of control, and high self-esteem, respectively. There was a significant correlation between self-esteem, locus of control and academic achievement of the students. Self-esteem accounted for 39.5% of the variation in academic achievement. It seems that interventions to increase self-esteem among student can help improve academic achievement among them.

The coalescent process in models with selection and recombination.

PubMed

Hudson, R R; Kaplan, N L

1988-11-01

The statistical properties of the process describing the genealogical history of a random sample of genes at a selectively neutral locus which is linked to a locus at which natural selection operates are investigated. It is found that the equations describing this process are simple modifications of the equations describing the process assuming that the two loci are completely linked. Thus, the statistical properties of the genealogical process for a random sample at a neutral locus linked to a locus with selection follow from the results obtained for the selected locus. Sequence data from the alcohol dehydrogenase (Adh) region of Drosophila melanogaster are examined and compared to predictions based on the theory. It is found that the spatial distribution of nucleotide differences between Fast and Slow alleles of Adh is very similar to the spatial distribution predicted if balancing selection operates to maintain the allozyme variation at the Adh locus. The spatial distribution of nucleotide differences between different Slow alleles of Adh do not match the predictions of this simple model very well.

Locus coeruleus and dopaminergic consolidation of everyday memory.

PubMed

Takeuchi, Tomonori; Duszkiewicz, Adrian J; Sonneborn, Alex; Spooner, Patrick A; Yamasaki, Miwako; Watanabe, Masahiko; Smith, Caroline C; Fernández, Guillén; Deisseroth, Karl; Greene, Robert W; Morris, Richard G M

2016-09-15

The retention of episodic-like memory is enhanced, in humans and animals, when something novel happens shortly before or after encoding. Using an everyday memory task in mice, we sought the neurons mediating this dopamine-dependent novelty effect, previously thought to originate exclusively from the tyrosine-hydroxylase-expressing (TH + ) neurons in the ventral tegmental area. Here we report that neuronal firing in the locus coeruleus is especially sensitive to environmental novelty, locus coeruleus TH + neurons project more profusely than ventral tegmental area TH + neurons to the hippocampus, optogenetic activation of locus coeruleus TH + neurons mimics the novelty effect, and this novelty-associated memory enhancement is unaffected by ventral tegmental area inactivation. Surprisingly, two effects of locus coeruleus TH + photoactivation are sensitive to hippocampal D 1 /D 5 receptor blockade and resistant to adrenoceptor blockade: memory enhancement and long-lasting potentiation of synaptic transmission in CA1 ex vivo. Thus, locus coeruleus TH + neurons can mediate post-encoding memory enhancement in a manner consistent with possible co-release of dopamine in the hippocampus.

The 3D Structure of the Immunoglobulin Heavy-Chain Locus: Implications for Long-Range Genomic Interactions

PubMed Central

Jhunjhunwala, Suchit; van Zelm, Menno C.; Peak, Mandy M.; Cutchin, Steve; Riblet, Roy; van Dongen, Jacques J.M.; Grosveld, Frank G.; Knoch, Tobias A.; Murre, Cornelis

2009-01-01

SUMMARY The immunoglobulin heavy-chain (Igh) locus is organized into distinct regions that contain multiple variable (VH), diversity (DH), joining (JH) and constant (CH) coding elements. How the Igh locus is structured in 3D space is unknown. To probe the topography of the Igh locus, spatial distance distributions were determined between 12 genomic markers that span the entire Igh locus. Comparison of the distance distributions to computer simulations of alternative chromatin arrangements predicted that the Igh locus is organized into compartments containing clusters of loops separated by linkers. Trilateration and triple-point angle measurements indicated the mean relative 3D positions of the VH, DH, JH, and CH elements, showed compartmentalization and striking conformational changes involving VH and DH-JH elements during early B cell development. In pro-B cells, the entire repertoire of VH regions (2 Mbp) appeared to have merged and juxtaposed to the DH elements, mechanistically permitting long-range genomic interactions to occur with relatively high frequency. PMID:18423198

Advances in stellar evolution; Proceedings of the Workshop on Stellar Ecology, Marciana Marina, Italy, June 23-29, 1996

NASA Astrophysics Data System (ADS)

Rood, R. T.; Renzini, A.

1997-01-01

The present volume on stellar evolution discusses fundamentals of stellar evolution and star clusters, variable stars, AGB stars and planetary nebulae, white dwarfs, binary star evolution, and stars in galaxies. Attention is given to the stellar population in the Galactic bulge, a photometric study of NGC 458, and HST observations of high-density globular clusters. Other topics addressed include the Cepheid instability strip in external galaxies, Hyades cluster white dwarfs and the initial-final mass relation, element diffusion in novae, mass function of the stars in the solar neighborhood, synthetic spectral indices for elliptical galaxies, and stars at the Galactic center.

Dependence of the clustering properties of galaxies on stellar velocity dispersion in the Main galaxy sample of SDSS DR10

NASA Astrophysics Data System (ADS)

Deng, Xin-Fa; Song, Jun; Chen, Yi-Qing; Jiang, Peng; Ding, Ying-Ping

2014-08-01

Using two volume-limited Main galaxy samples of the Sloan Digital Sky Survey Data Release 10 (SDSS DR10), we investigate the dependence of the clustering properties of galaxies on stellar velocity dispersion by cluster analysis. It is found that in the luminous volume-limited Main galaxy sample, except at r=1.2, richer and larger systems can be more easily formed in the large stellar velocity dispersion subsample, while in the faint volume-limited Main galaxy sample, at r≥0.9, an opposite trend is observed. According to statistical analyses of the multiplicity functions, we conclude in two volume-limited Main galaxy samples: small stellar velocity dispersion galaxies preferentially form isolated galaxies, close pairs and small group, while large stellar velocity dispersion galaxies preferentially inhabit the dense groups and clusters. However, we note the difference between two volume-limited Main galaxy samples: in the faint volume-limited Main galaxy sample, at r≥0.9, the small stellar velocity dispersion subsample has a higher proportion of galaxies in superclusters ( n≥200) than the large stellar velocity dispersion subsample.

Model structure of a cosmic-ray mediated stellar or solar wind

NASA Technical Reports Server (NTRS)

Lee, M. A.; Axford, W. I.

1988-01-01

An idealized hydrodynamic model is presented for the mediation of a free-streaming stellar wind by galactic cosmic rays or energetic particles accelerated at the stellar wind termination shock. The spherically-symmetric stellar wind is taken to be cold; the only body force is the cosmic ray pressure gradient. The cosmic rays are treated as a massless fluid with an effective mean diffusion coefficient k proportional to radial distance r. The structure of the governing equations is investigated both analytically and numerically. Solutions for a range of values of k are presented which describe the deceleration of the stellar wind and a transition to nearly incompressible flow and constant cosmic ray pressure at large r. In the limit of small k the transition steepens to a strong stellar wind termination shock. For large k the stellar wind is decelerated gradually with no shock transition. It is argued that the solutions provide a simple model for the mediation of the solar wind by interstellar ions as both pickup ions and the cosmic ray anomalous component which together dominate the pressure of the solar wind at large r.

Construction concepts and validation of the 3D printed UST_2 modular stellarator

NASA Astrophysics Data System (ADS)

Queral, V.

2015-03-01

High accuracy, geometric complexity and thus high cost of stellarators tend to hinder the advance of stellarator research. Nowadays, new manufacturing methods might be developed for the production of small and middle-size stellarators. The methods should demonstrate advantages with respect common fabrication methods, like casting, cutting, forging and welding, for the construction of advanced highly convoluted modular stellarators. UST2 is a small modular three period quasi-isodynamic stellarator of major radius 0.26 m and plasma volume 10 litres being currently built to validate additive manufacturing (3D printing) for stellarator construction. The modular coils are wound in grooves defined on six 3D printed half period frames designed as light truss structures filled by a strong filler. A geometrically simple assembling configuration has been concocted for UST2 so as to try to lower the cost of the device while keeping the positioning accuracy of the different elements. The paper summarizes the construction and assembling concepts developed, the devised positioning methodology, the design of the coil frames and positioning elements and, an initial validation of the assembling of the components.

Getting to the core of locus of control: Is it an evaluation of the self or the environment?

PubMed

Johnson, Russell E; Rosen, Christopher C; Chang, Chu-Hsiang Daisy; Lin, Szu-Han Joanna

2015-09-01

Responding to criticisms surrounding the structural validity of the higher order core self-evaluations (CSE) construct, in the current study we examined the appropriateness of including locus of control as an indicator of CSE. Drawing from both theoretical and empirical evidence, we argue that locus of control is more heavily influenced by evaluations of the environment compared with the other CSE traits. Using data from 4 samples, we demonstrate that model fit for the higher order CSE construct is better when locus of control is excluded versus included as a trait indicator and that the shared variance between locus of control and CSE is nominal. This does not mean that locus of control is irrelevant for CSE theory though. We propose that evaluations of the environment moderate the relations that CSE has with its outcomes. To test this proposition, we collected data from 4 unique samples that included a mix of student and employee participants, self- and other-ratings, and cross-sectional and longitudinal data. Our results revealed that locus of control moderated relations of CSE with life and job satisfaction, and supervisor-rated job performance. CSE had stronger, positive relations with these outcomes when locus of control is internal versus external. These findings broaden CSE theory by demonstrating one way in which evaluations of the environment interface with evaluations of the self. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

Resolving the Conflict Between Associative Overdominance and Background Selection

PubMed Central

Zhao, Lei; Charlesworth, Brian

2016-01-01

In small populations, genetic linkage between a polymorphic neutral locus and loci subject to selection, either against partially recessive mutations or in favor of heterozygotes, may result in an apparent selective advantage to heterozygotes at the neutral locus (associative overdominance) and a retardation of the rate of loss of variability by genetic drift at this locus. In large populations, selection against deleterious mutations has previously been shown to reduce variability at linked neutral loci (background selection). We describe analytical, numerical, and simulation studies that shed light on the conditions under which retardation vs. acceleration of loss of variability occurs at a neutral locus linked to a locus under selection. We consider a finite, randomly mating population initiated from an infinite population in equilibrium at a locus under selection. With mutation and selection, retardation occurs only when S, the product of twice the effective population size and the selection coefficient, is of order 1. With S >> 1, background selection always causes an acceleration of loss of variability. Apparent heterozygote advantage at the neutral locus is, however, always observed when mutations are partially recessive, even if there is an accelerated rate of loss of variability. With heterozygote advantage at the selected locus, loss of variability is nearly always retarded. The results shed light on experiments on the loss of variability at marker loci in laboratory populations and on the results of computer simulations of the effects of multiple selected loci on neutral variability. PMID:27182952

An apodized Kepler periodogram for separating planetary and stellar activity signals

PubMed Central

Gregory, Philip C.

2016-01-01

A new apodized Keplerian (AK) model is proposed for the analysis of precision radial velocity (RV) data to model both planetary and stellar activity (SA) induced RV signals. A symmetrical Gaussian apodization function with unknown width and centre can distinguish planetary signals from SA signals on the basis of the span of the apodization window. The general model for m AK signals includes a linear regression term between RV and the SA diagnostic log (R′hk), as well as an extra Gaussian noise term with unknown standard deviation. The model parameters are explored using a Bayesian fusion Markov chain Monte Carlo code. A differential version of the generalized Lomb–Scargle periodogram that employs a control diagnostic provides an additional way of distinguishing SA signals and helps guide the choice of new periods. Results are reported for a recent international RV blind challenge which included multiple state-of-the-art simulated data sets supported by a variety of SA diagnostics. In the current implementation, the AK method achieved a reduction in SA noise by a factor of approximately 6. Final parameter estimates for the planetary candidates are derived from fits that include AK signals to model the SA components and simple Keplerians to model the planetary candidates. Preliminary results are also reported for AK models augmented by a moving average component that allows for correlations in the residuals. PMID:27346979

Physical Attractiveness, Locus of Control, Sex Role, and Conversational Assertiveness.

ERIC Educational Resources Information Center

Campbell, Keith F.; And Others

1990-01-01

Analyzes the relationship among physical attractiveness, locus of control, sex role orientation, and assertiveness in undergraduate students. Reviews videotapes of mixed-sex student groups engaged in discussion. Finds an internal locus of control positively correlated with assertiveness. Uses a behavioral measure of assertiveness rather than…

Photospheres of hot stars. IV - Spectral type O4

NASA Technical Reports Server (NTRS)

Bohannan, Bruce; Abbott, David C.; Voels, Stephen A.; Hummer, David G.

1990-01-01

The basic stellar parameters of a supergiant (Zeta Pup) and two main-sequence stars, 9 Sgr and HD 46223, at spectral class O4 are determined using line profile analysis. The stellar parameters are determined by comparing high signal-to-noise hydrogen and helium line profiles with those from stellar atmosphere models which include the effect of radiation scattered back onto the photosphere from an overlying stellar wind, an effect referred to as wind blanketing. At spectral class O4, the inclusion of wind-blanketing in the model atmosphere reduces the effective temperature by an average of 10 percent. This shift in effective temperature is also reflected by shifts in several other stellar parameters relative to previous O4 spectral-type calibrations. It is also shown through the analysis of the two O4 V stars that scatter in spectral type calibrations is introduced by assuming that the observed line profile reflects the photospheric stellar parameters.

Particle tagging and its implications for stellar population dynamics

NASA Astrophysics Data System (ADS)

Le Bret, Theo; Pontzen, Andrew; Cooper, Andrew P.; Frenk, Carlos; Zolotov, Adi; Brooks, Alyson M.; Governato, Fabio; Parry, Owen H.

2017-07-01

We establish a controlled comparison between the properties of galactic stellar haloes obtained with hydrodynamical simulations and with 'particle tagging'. Tagging is a fast way to obtain stellar population dynamics: instead of tracking gas and star formation, it 'paints' stars directly on to a suitably defined subset of dark matter particles in a collisionless, dark-matter-only simulation. Our study shows that 'live' particle tagging schemes, where stellar masses are painted on to the dark matter particles dynamically throughout the simulation, can generate good fits to the hydrodynamical stellar density profiles of a central Milky Way-like galaxy and its most prominent substructure. Energy diffusion processes are crucial to reshaping the distribution of stars in infalling spheroidal systems and hence the final stellar halo. We conclude that the success of any particular tagging scheme hinges on this diffusion being taken into account, and discuss the role of different subgrid feedback prescriptions in driving this diffusion.

Assessing the Effect of Stellar Companions to Kepler Objects of Interest

NASA Astrophysics Data System (ADS)

Hirsch, Lea; Ciardi, David R.; Howard, Andrew

2017-01-01

Unknown stellar companions to Kepler planet host stars dilute the transit signal, causing the planetary radii to be underestimated. We report on the analysis of 165 stellar companions detected with high-resolution imaging to be within 2" of 159 KOI host stars. The majority of the planets and planet candidates in these systems have nominal radii smaller than 6 REarth. Using multi-filter photometry on each companion, we assess the likelihood that the companion is bound and estimate its stellar properties, including stellar radius and flux. We then recalculate the planet radii in these systems, determining how much each planet's size is underestimated if it is assumed to 1) orbit the primary star, 2) orbit the companion star, or 3) be equally likely to orbit either star in the system. We demonstrate the overall effect of unknown stellar companions on our understanding of Kepler planet sizes.

Thermonuclear inverse magnetic pumping power cycle for stellarator reactor

DOEpatents

Ho, Darwin D.; Kulsrud, Russell M.

1991-01-01

The plasma column in a stellarator is compressed and expanded alternatively in minor radius. First a plasma in thermal balance is compressed adiabatically. The volume of the compressed plasma is maintained until the plasma reaches a new thermal equilibrium. The plasma is then expanded to its original volume. As a result of the way a stellarator works, the plasma pressure during compression is less than the corresponding pressure during expansion. Therefore, negative work is done on the plasma over a complete cycle. This work manifests itself as a back-voltage in the toroidal field coils. Direct electrical energy is obtained from this voltage. Alternatively, after the compression step, the plasma can be expanded at constant pressure. The cycle can be made self-sustaining by operating a system of two stellarator reactors in tandem. Part of the energy derived from the expansion phase of a first stellarator reactor is used to compress the plasma in a second stellarator reactor.

Reevaluating the serotype II capsular locus of Streptococcus agalactiae.

PubMed

Martins, E R; Melo-Cristino, J; Ramirez, M

2007-10-01

We report a novel sequence of the serotype II capsular locus of group B streptococcus that resolves inconsistencies among the results of various groups and the sequence in GenBank. This locus was found in diverse lineages and presents genes consistent with the complete synthesis of the type II polysaccharide.

Analysis techniques for multivariate root loci. [a tool in linear control systems

NASA Technical Reports Server (NTRS)

Thompson, P. M.; Stein, G.; Laub, A. J.

1980-01-01

Analysis and techniques are developed for the multivariable root locus and the multivariable optimal root locus. The generalized eigenvalue problem is used to compute angles and sensitivities for both types of loci, and an algorithm is presented that determines the asymptotic properties of the optimal root locus.

Discrimination of Pathogenic Versus Non-Pathogenic Yersinia Pestis and Escherichia Coli Using Proteomics Mass Spectrometry

DTIC Science & Technology

2010-05-01

protein 1b (lb;c) thiol peroxidase attachment invasion locus protein trigger factor 50S ribosomal protein L9 urease (urea amidohydrolase) beta...subunit attachment invasion locus protein urease (urea amidohydrolase) beta subunit attachment invasion locus protein hypothetical protein y2159

Locus of control, sources of motivation, and mental boundaries as antecedents of leader-member exchange quality.

PubMed

Barbuto, John E; Finch, Weltmer Dayna; Pennisi, Lisa A

2010-02-01

In this study were examined leaders' and members' scores on locus of control, sources of motivation, and mental boundaries to predict the quality of leader-member exchanges. 80 elected officials and their 388 direct reports were sampled in a field study. Analysis indicated followers' scores on locus of control, leaders' scores of self-concept internal motivation, leaders' scores on locus of control, and followers' rated goal-internalization motivation were positively related to leader-member exchanges. Implications and directions for research are discussed.

The diabetes type 1 locus Idd6 modulates activity of CD4+CD25+ regulatory T-cells.

PubMed

Rogner, Ute Christine; Lepault, Françoise; Gagnerault, Marie-Claude; Vallois, David; Morin, Joëlle; Avner, Philip; Boitard, Christian

2006-01-01

The genetic locus Idd6 confers susceptibility to the spontaneous development of type 1 diabetes in the NOD mouse. Our studies on disease resistance of the congenic mouse strain NOD.C3H 6.VIII showed that Idd6 influences T-cell activities in the peripheral immune system and suggest that a major mechanism by which the Idd6 locus modifies diabetes development is via modulation of regulatory T-cell activities. Our transfer experiments using total splenocytes and purified T-cells demonstrated that the locus specifically controls the efficiency of disease protection mediated by the regulatory CD4(+)CD25(+) T-cell subset. Our data also implicate the Idd6 locus in controlling the balance between infiltrating lymphocytes and antigen-presenting cells within the pancreatic islet.

Predictors of Parental Locus of Control in Mothers of Pre- and Early-Adolescents

PubMed Central

Freed, Rachel D.; Tompson, Martha C.

2016-01-01

Parental locus of control refers to parents’ perceived power and efficacy in child-rearing situations. This study explored parental locus of control and its correlates in 160 mothers of children ages 8–14 cross-sectionally and 1 year later. Maternal depression, maternal expressed emotion, and child internalizing and externalizing behavior were examined, along with a number of sociodemographic factors. Cross-sectional analyses indicated that external parental locus of control was associated with child externalizing behavior, maternal depression, less maternal education, lower income, and older maternal age. Longitudinal analyses showed that child age and externalizing behavior also predicted increases in external parental locus of control 1 year later. Finally, lower income and less parental perceived control predicted increases in child externalizing behavior over time. PMID:21229447

Vocational interests of adolescents: relationships between self-esteem and locus of control.

PubMed

Mullis, A K; Mullis, R L

1997-12-01

The purpose of this study was to examine relationships among scores on vocational interests, self-esteem, and locus of control for high school students. Grade and sex differences were also examined. 1364 high school students ranging in age from 14 to 19 years of age were administered the Coopersmith Self-esteem Inventory, Nowicki-Strickland Locus of Control Scale for Children, and the Strong-Campbell Interest Inventory. High school students with higher scores on self-esteem and showing an orientation toward internal locus of control expressed more interests in a variety of vocational themes than adolescents with lower scores on self-esteem and scores for external locus of control. Sex and grade differences in vocational interests of adolescents were also noted. The findings were discussed in light of theoretical and practical considerations.

TRACING THE EVOLUTION OF HIGH-REDSHIFT GALAXIES USING STELLAR ABUNDANCES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crosby, Brian D.; O’Shea, Brian W.; Beers, Timothy C.

2016-03-20

This paper presents the first results from a model for chemical evolution that can be applied to N-body cosmological simulations and quantitatively compared to measured stellar abundances from large astronomical surveys. This model convolves the chemical yield sets from a range of stellar nucleosynthesis calculations (including asymptotic giant branch stars, Type Ia and II supernovae, and stellar wind models) with a user-specified stellar initial mass function (IMF) and metallicity to calculate the time-dependent chemical evolution model for a “simple stellar population” (SSP) of uniform metallicity and formation time. These SSP models are combined with a semianalytic model for galaxy formation andmore » evolution that uses merger trees from N-body cosmological simulations to track several α- and iron-peak elements for the stellar and multiphase interstellar medium components of several thousand galaxies in the early (z ≥ 6) universe. The simulated galaxy population is then quantitatively compared to two complementary data sets of abundances in the Milky Way stellar halo and is capable of reproducing many of the observed abundance trends. The observed abundance ratio distributions are best reproduced with a Chabrier IMF, a chemically enriched star formation efficiency of 0.2, and a redshift of reionization of 7. Many abundances are qualitatively well matched by our model, but our model consistently overpredicts the carbon-enhanced fraction of stars at low metallicities, likely owing to incomplete coverage of Population III stellar yields and supernova models and the lack of dust as a component of our model.« less

Stellar Velocity Dispersion: Linking Quiescent Galaxies to Their Dark Matter Halos

NASA Astrophysics Data System (ADS)

Zahid, H. Jabran; Sohn, Jubee; Geller, Margaret J.

2018-06-01

We analyze the Illustris-1 hydrodynamical cosmological simulation to explore the stellar velocity dispersion of quiescent galaxies as an observational probe of dark matter halo velocity dispersion and mass. Stellar velocity dispersion is proportional to dark matter halo velocity dispersion for both central and satellite galaxies. The dark matter halos of central galaxies are in virial equilibrium and thus the stellar velocity dispersion is also proportional to dark matter halo mass. This proportionality holds even when a line-of-sight aperture dispersion is calculated in analogy to observations. In contrast, at a given stellar velocity dispersion, the dark matter halo mass of satellite galaxies is smaller than virial equilibrium expectations. This deviation from virial equilibrium probably results from tidal stripping of the outer dark matter halo. Stellar velocity dispersion appears insensitive to tidal effects and thus reflects the correlation between stellar velocity dispersion and dark matter halo mass prior to infall. There is a tight relation (≲0.2 dex scatter) between line-of-sight aperture stellar velocity dispersion and dark matter halo mass suggesting that the dark matter halo mass may be estimated from the measured stellar velocity dispersion for both central and satellite galaxies. We evaluate the impact of treating all objects as central galaxies if the relation we derive is applied to a statistical ensemble. A large fraction (≳2/3) of massive quiescent galaxies are central galaxies and systematic uncertainty in the inferred dark matter halo mass is ≲0.1 dex thus simplifying application of the simulation results to currently available observations.

The Influence of Atomic Diffusion on Stellar Ages and Chemical Tagging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dotter, Aaron; Conroy, Charlie; Cargile, Phillip

2017-05-10

In the era of large stellar spectroscopic surveys, there is an emphasis on deriving not only stellar abundances but also the ages for millions of stars. In the context of Galactic archeology, stellar ages provide a direct probe of the formation history of the Galaxy. We use the stellar evolution code MESA to compute models with atomic diffusion—with and without radiative acceleration—and extra mixing in the surface layers. The extra mixing consists of both density-dependent turbulent mixing and envelope overshoot mixing. Based on these models we argue that it is important to distinguish between initial, bulk abundances (parameters) and current,more » surface abundances (variables) in the analysis of individual stellar ages. In stars that maintain radiative regions on evolutionary timescales, atomic diffusion modifies the surface abundances. We show that when initial, bulk metallicity is equated with current, surface metallicity in isochrone age analysis, the resulting stellar ages can be systematically overestimated by up to 20%. The change of surface abundances with evolutionary phase also complicates chemical tagging, which is the concept that dispersed star clusters can be identified through unique, high-dimensional chemical signatures. Stars from the same cluster, but in different evolutionary phases, will show different surface abundances. We speculate that calibration of stellar models may allow us to estimate not only stellar ages but also initial abundances for individual stars. In the meantime, analyzing the chemical properties of stars in similar evolutionary phases is essential to minimize the effects of atomic diffusion in the context of chemical tagging.« less

SDSS-IV MaNGA: modelling the metallicity gradients of gas and stars - radially dependent metal outflow versus IMF

NASA Astrophysics Data System (ADS)

Lian, Jianhui; Thomas, Daniel; Maraston, Claudia; Goddard, Daniel; Parikh, Taniya; Fernández-Trincado, J. G.; Roman-Lopes, Alexandre; Rong, Yu; Tang, Baitian; Yan, Renbin

2018-05-01

In our previous work, we found that only two scenarios are capable of reproducing the observed integrated mass-metallicity relations for the gas and stellar components of local star-forming galaxies simultaneously. One scenario invokes a time-dependent metal outflow loading factor with stronger outflows at early times. The other scenario uses a time-dependent initial mass function (IMF) slope with a steeper IMF at early times. In this work, we extend our study to investigate the radial profile of gas and stellar metallicity in local star-forming galaxies using spatially resolved spectroscopic data from the SDSS-IV MaNGA survey. We find that most galaxies show negative gradients in both gas and stellar metallicity with steeper gradients in stellar metallicity. The stellar metallicity gradients tend to be mass dependent with steeper gradients in more massive galaxies while no clear mass dependence is found for the gas metallicity gradient. Then we compare the observations with the predictions from a chemical evolution model of the radial profiles of gas and stellar metallicities. We confirm that the two scenarios proposed in our previous work are also required to explain the metallicity gradients. Based on these two scenarios, we successfully reproduce the radial profiles of gas metallicity, stellar metallicity, stellar mass surface density, and star formation rate surface density simultaneously. The origin of the negative gradient in stellar metallicity turns out to be driven by either radially dependent metal outflow or IMF slope. In contrast, the radial dependence of the gas metallicity is less constrained because of the degeneracy in model parameters.

A Third Locus for Autosomal Dominant Cerebellar Ataxia Type 1 Maps to Chromosome 14q24.3-qter: Evidence for the Existence of a Fourth Locus

PubMed Central

Stevanin, Giovanni; Le Guern, Eric; Ravisé, Nicole; Chneiweiss, Hervé; Dürr, Alexandra; Cancel, Géraldine; Vignal, Alain; Boch, Anne-Laure; Ruberg, Merle; Penet, Christiane; Pothin, Yolaine; Lagroua, Isabelle; Haguenau, Michel; Rancurel, Gérald; Weissenbach, Jean; Agid, Yves; Brice, Alexis

1994-01-01

The autosomal dominant cerebellar ataxias (ADCA) type I are a group of neurological disorders that are clinically and genetically heterogeneous. Two genes implicated in the disease, SCA1 (spinal cerebellar ataxia 1) and SCA2, are already localized. We have mapped a third locus to chromosome 14q24.3-qter, by linkage analysis in a non-SCA1/non-SCA2 family and have confirmed its existence in a second such family. We suggest designating this new locus “SCA3.” Combined analysis of the two families restricted the SCA3 locus to a 15-cM interval between markers D14S67 and D14S81. The gene for Machado-Joseph disease (MJD), a clinically different form of ADCA type I, has been recently assigned to chromosome 14q24.3-q32. Although the SCA3 locus is within the MJD region, linkage analyses cannot yet demonstrate whether they result from mutations of the same gene. Linkage to all three loci (SCA1, SCA2, and SCA3) was excluded in another family, which indicates the existence of a fourth ADCA type I locus. PMID:8279460

The unusual S locus of Leavenworthia is composed of two sets of paralogous loci.

PubMed

Chantha, Sier-Ching; Herman, Adam C; Castric, Vincent; Vekemans, Xavier; Marande, William; Schoen, Daniel J

2017-12-01

The Leavenworthia self-incompatibility locus (S locus) consists of paralogs (Lal2, SCRL) of the canonical Brassicaceae S locus genes (SRK, SCR), and is situated in a genomic position that differs from the ancestral one in the Brassicaceae. Unexpectedly, in a small number of Leavenworthia alabamica plants examined, sequences closely resembling exon 1 of SRK have been found, but the function of these has remained unclear. BAC cloning and expression analyses were employed to characterize these SRK-like sequences. An SRK-positive Bacterial Artificial Chromosome clone was found to contain complete SRK and SCR sequences located close by one another in the derived genomic position of the Leavenworthia S locus, and in place of the more typical Lal2 and SCRL sequences. These sequences are expressed in stigmas and anthers, respectively, and crossing data show that the SRK/SCR haplotype is functional in self-incompatibility. Population surveys indicate that < 5% of Leavenworthia S loci possess such alleles. An ancestral translocation or recombination event involving SRK/SCR and Lal2/SCRL likely occurred, together with neofunctionalization of Lal2/SCRL, and both haplotype groups now function as Leavenworthia S locus alleles. These findings suggest that S locus alleles can have distinctly different evolutionary origins. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Fixation probability in a two-locus intersexual selection model.

PubMed

Durand, Guillermo; Lessard, Sabin

2016-06-01

We study a two-locus model of intersexual selection in a finite haploid population reproducing according to a discrete-time Moran model with a trait locus expressed in males and a preference locus expressed in females. We show that the probability of ultimate fixation of a single mutant allele for a male ornament introduced at random at the trait locus given any initial frequency state at the preference locus is increased by weak intersexual selection and recombination, weak or strong. Moreover, this probability exceeds the initial frequency of the mutant allele even in the case of a costly male ornament if intersexual selection is not too weak. On the other hand, the probability of ultimate fixation of a single mutant allele for a female preference towards a male ornament introduced at random at the preference locus is increased by weak intersexual selection and weak recombination if the female preference is not costly, and is strong enough in the case of a costly male ornament. The analysis relies on an extension of the ancestral recombination-selection graph for samples of haplotypes to take into account events of intersexual selection, while the symbolic calculation of the fixation probabilities is made possible in a reasonable time by an optimizing algorithm. Copyright © 2016 Elsevier Inc. All rights reserved.

EsrE-A yigP Locus-Encoded Transcript-Is a 3′ UTR sRNA Involved in the Respiratory Chain of E. coli

PubMed Central

Xia, Hui; Yang, Xichen; Tang, Qiongwei; Ye, Jiang; Wu, Haizhen; Zhang, Huizhan

2017-01-01

The yigP locus is widely conserved among γ-proteobacteria. Mutation of the yigP locus impacts aerobic growth of Gram-negative bacteria. However, the underlying mechanism of how the yigP locus influences aerobic growth remains largely unknown. Here, we demonstrated that the yigP locus in Escherichia coli encodes two transcripts; the mRNA of ubiquinone biosynthesis protein, UbiJ, and the 3′ untranslated region small regulatory RNA (sRNA), EsrE. EsrE is an independent transcript that is transcribed using an internal promoter of the yigP locus. Surprisingly, we found that both the EsrE sRNA and UbiJ protein were required for Q8 biosynthesis, and were sufficient to rescue the growth defect ascribed to deletion of the yigP locus. Moreover, our data showed that EsrE targeted multiple mRNAs involved in several cellular processes including murein biosynthesis and the tricarboxylic acid cycle. Among these targets, sdhD mRNA that encodes one subunit of succinate dehydrogenase (SDH), was significantly activated. Our findings provided an insight into the important function of EsrE in bacterial adaptation to various environments, as well as coordinating different aspects of bacterial physiology. PMID:28900423

Detailed dissection of the chromosomal region containing the Ph1 locus in wheat Triticum aestivum: with deletion mutants and expression profiling.

PubMed

Al-Kaff, Nadia; Knight, Emilie; Bertin, Isabelle; Foote, Tracie; Hart, Nicola; Griffiths, Simon; Moore, Graham

2008-04-01

Understanding Ph1, a dominant homoeologous chromosome pairing suppressor locus on the long arm of chromosome 5B in wheat Triticum aestivum L., is the core of the investigation in this article. The Ph1 locus restricts chromosome pairing and recombination at meiosis to true homologues. The importance of wheat as a crop and the need to exploit its wild relatives as donors for economically important traits in wheat breeding programmes is the main drive to uncover the mechanism of the Ph1 locus and regulate its activity. Following the molecular genetic characterization of the Ph1 locus, five additional deletion mutants covering the region have been identified. In addition, more bacterial artificial chromosomes (BACs) were sequenced and analysed to elucidate the complexity of this locus. A semi-quantitative RT-PCR was used to compare the expression profiles of different genes in the 5B region containing the Ph1 locus with their homoeologues on 5A and 5D. PCR products were cloned and sequenced to identify the gene from which they were derived. Deletion mutants and expression profiling of genes in the region containing the Ph1 locus on 5B has further restricted Ph1 to a cluster of cdk-like genes. Bioinformatic analysis of the cdk-like genes revealed their close homology to the checkpoint kinase Cdk2 from humans. Cdk2 is involved in the initiation of replication and is required in early meiosis. Expression profiling has revealed that the cdk-like gene cluster is unique within the region analysed on 5B in that these genes are transcribed. Deletion of the cdk-like locus on 5B results in activation of transcription of functional cdk-like copies on 5A and 5D. Thus the cdk locus on 5B is dominant to those on 5A and 5D in determining the overall activity, which will be dependent on a complex interplay between transcription from non-functional and functional cdk-like genes. The Ph1 locus has been defined to a cdk-like gene cluster related to Cdk2 in humans, a master checkpoint gene involved in the initiation of replication and required for early meiosis.

Effectiveness of teaching cognitive-behavioral techniques on locus of control in hemodialysis patients

PubMed Central

Mehrtak, Mohammad; Habibzadeh, Shahram; Farzaneh, Esmaeil; Rjaei-Khiavi, Abdollah

2017-01-01

Background Many of the cognitive behavioral models and therapeutic protocols developed so far for psychological disorders and chronic diseases have proved effective through clinical research. Objective This study aimed to determine the effectiveness of teaching cognitive-behavioral techniques on locus of control in hemodialysis patients. Methods This controlled clinical trial study was conducted in 2015 with 76 patients selected by census and treated with a hemodialysis machine in the dialysis department of Vali-Asr Hospital in the city of Meshkinshahr. A total of four patients were excluded because of their critical conditions while the rest, who were recruited, were randomly divided into two equal groups of 36 patients as the intervention and control groups. First, the locus of control was measured in both groups through a pretest, and cognitive-behavioral techniques were then taught to the intervention group during eight 45 to 90-minute sessions. The locus of control in patients of both groups was finally re-measured through a posttest. Data were collected using Rotter’s Locus of Control Inventory. The Wilcoxon test and Mann–Whitney U test were respectively used in SPSS18 for data analysis. Results In the pretest and posttest stages respectively, 4.8% and 14.3% of samples in the control group as well as 14.3% and 33.3% of samples in the intervention group enjoyed internal locus of control. The difference between the pretest and posttest scores of internal locus of control in the intervention group was significant (p=0.004), which indicates the positive effect of cognitive-behavioral psychotherapeutic intervention on internalization of locus of control in this group. Conclusions Given the external locus of control in most of the study patients and also the positive significant effect of cognitive-behavioral psychotherapy on internalization of locus of control in this group of patients, it appears necessary to have a psychology resident present in the hemodialysis department to teach the necessary cognitive-behavioral techniques to internalize the locus of control. Trial registration The trial was registered at the Thai Clinical Trial Registry (http://www.clinicaltrials.in.th) with the TCTID: TCTR20170707003. Funding The authors received no financial support for the research, authorship, and/or publication of this article. PMID:29238508

Deriving stellar parameters with the SME software package

NASA Astrophysics Data System (ADS)

Piskunov, N.

2017-09-01

Photometry and spectroscopy are complementary tools for deriving accurate stellar parameters. Here I present one of the popular packages for stellar spectroscopy called SME with the emphasis on the latest developments and error assessment for the derived parameters.

Chemical element transport in stellar evolution models

PubMed Central

Cassisi, Santi

2017-01-01

Stellar evolution computations provide the foundation of several methods applied to study the evolutionary properties of stars and stellar populations, both Galactic and extragalactic. The accuracy of the results obtained with these techniques is linked to the accuracy of the stellar models, and in this context the correct treatment of the transport of chemical elements is crucial. Unfortunately, in many respects calculations of the evolution of the chemical abundance profiles in stars are still affected by sometimes sizable uncertainties. Here, we review the various mechanisms of element transport included in the current generation of stellar evolution calculations, how they are implemented, the free parameters and uncertainties involved, the impact on the models and the observational constraints. PMID:28878972

Program Package for the Analysis of High Resolution High Signal-To-Noise Stellar Spectra

NASA Astrophysics Data System (ADS)

Piskunov, N.; Ryabchikova, T.; Pakhomov, Yu.; Sitnova, T.; Alekseeva, S.; Mashonkina, L.; Nordlander, T.

2017-06-01

The program package SME (Spectroscopy Made Easy), designed to perform an analysis of stellar spectra using spectral fitting techniques, was updated due to adding new functions (isotopic and hyperfine splittins) in VALD and including grids of NLTE calculations for energy levels of few chemical elements. SME allows to derive automatically stellar atmospheric parameters: effective temperature, surface gravity, chemical abundances, radial and rotational velocities, turbulent velocities, taking into account all the effects defining spectral line formation. SME package uses the best grids of stellar atmospheres that allows us to perform spectral analysis with the similar accuracy in wide range of stellar parameters and metallicities - from dwarfs to giants of BAFGK spectral classes.

Chemical element transport in stellar evolution models.

PubMed

Salaris, Maurizio; Cassisi, Santi

2017-08-01

Stellar evolution computations provide the foundation of several methods applied to study the evolutionary properties of stars and stellar populations, both Galactic and extragalactic. The accuracy of the results obtained with these techniques is linked to the accuracy of the stellar models, and in this context the correct treatment of the transport of chemical elements is crucial. Unfortunately, in many respects calculations of the evolution of the chemical abundance profiles in stars are still affected by sometimes sizable uncertainties. Here, we review the various mechanisms of element transport included in the current generation of stellar evolution calculations, how they are implemented, the free parameters and uncertainties involved, the impact on the models and the observational constraints.

Theoretical Re-evaluations of Scaling Relations between SMBHs and Their Host Galaxies - 2. Importance of AGN Feedback Suggested by Stellar Age - Velocity Dispersion Relation

NASA Astrophysics Data System (ADS)

Shirakata, Hikari; Kawaguchi, Toshihiro; Okamoto, Takashi; Ishiyama, Tomoaki

2017-09-01

We present the galactic stellar age - velocity dispersion relation obtained from a semi-analytic model of galaxy formation. We divide galaxies into two populations: galaxies which have over-massive/under-massive black holes (BHs) against the best-fitting BH mass - velocity dispersion relation. We find that galaxies with larger velocity dispersion have older stellar ages. We also find that galaxies with over-massive BHs have older stellar ages. These results are consistent with observational results obtained from Martin-Navarro et al. (2016). We tested the model with weak AGN feedback and find that galaxies with larger velocity dispersion have a younger stellar age.

Cluster galaxy population evolution from the Subaru Hyper Suprime-Cam survey: brightest cluster galaxies, stellar mass distribution, and active galaxies

NASA Astrophysics Data System (ADS)

Lin, Yen-Ting; Hsieh, Bau-Ching; Lin, Sheng-Chieh; Oguri, Masamune; Chen, Kai-Feng; Tanaka, Masayuki; Chiu, I.-non; Huang, Song; Kodama, Tadayuki; Leauthaud, Alexie; More, Surhud; Nishizawa, Atsushi J.; Bundy, Kevin; Lin, Lihwai; Miyazaki, Satoshi; HSC Collaboration

2018-01-01

The unprecedented depth and area surveyed by the Subaru Strategic Program with the Hyper Suprime-Cam (HSC-SSP) have enabled us to construct and publish the largest distant cluster sample out to z~1 to date. In this exploratory study of cluster galaxy evolution from z=1 to z=0.3, we investigate the stellar mass assembly history of brightest cluster galaxies (BCGs), and evolution of stellar mass and luminosity distributions, stellar mass surface density profile, as well as the population of radio galaxies. Our analysis is the first high redshift application of the top N richest cluster selection, which is shown to allow us to trace the cluster galaxy evolution faithfully. Our stellar mass is derived from a machine-learning algorithm, which we show to be unbiased and accurate with respect to the COSMOS data. We find very mild stellar mass growth in BCGs, and no evidence for evolution in both the total stellar mass-cluster mass correlation and the shape of the stellar mass surface density profile. The clusters are found to contain more red galaxies compared to the expectations from the field, even after the differences in density between the two environments have been taken into account. We also present the first measurement of the radio luminosity distribution in clusters out to z~1.

Two chemically similar stellar overdensities on opposite sides of the plane of the Galactic disk

DOE PAGES

Bergemann, Maria; Sesar, Branimir; Cohen, Judith G.; ...

2018-02-26

Our Galaxy is thought to have undergone an active evolutionary history dominated by star formation, the accretion of cold gas, and, in particular, mergers up to 10 gigayear ago. The stellar halo reveals rich fossil evidence of these interactions in the form of stellar streams, substructures, and chemically distinct stellar components. The impact of dwarf galaxy mergers on the content and morphology of the Galactic disk is still being explored. Recent studies have identified kinematically distinct stellar substructures and moving groups, which may have extragalactic origin. However, there is mounting evidence that stellar overdensities at the outer disk/halo interface couldmore » have been caused by the interaction of a dwarf galaxy with the disk. Here we report detailed spectroscopic analysis of 14 stars drawn from two stellar overdensities, each lying about 5 kiloparsecs above and below the Galactic plane - locations suggestive of association with the stellar halo. However, we find that the chemical compositions of these stars are almost identical, both within and between these groups, and closely match the abundance patterns of the Milky Way disk stars. This study hence provides compelling evidence that these stars originate from the disk and the overdensities they are part of were created by tidal interactions of the disk with passing or merging dwarf galaxies.« less

THE SL2S GALAXY-SCALE LENS SAMPLE. V. DARK MATTER HALOS AND STELLAR IMF OF MASSIVE EARLY-TYPE GALAXIES OUT TO REDSHIFT 0.8

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sonnenfeld, Alessandro; Treu, Tommaso; Marshall, Philip J.

2015-02-20

We investigate the cosmic evolution of the internal structure of massive early-type galaxies over half of the age of the universe. We perform a joint lensing and stellar dynamics analysis of a sample of 81 strong lenses from the Strong Lensing Legacy Survey and Sloan ACS Lens Survey and combine the results with a hierarchical Bayesian inference method to measure the distribution of dark matter mass and stellar initial mass function (IMF) across the population of massive early-type galaxies. Lensing selection effects are taken into account. We find that the dark matter mass projected within the inner 5 kpc increasesmore » for increasing redshift, decreases for increasing stellar mass density, but is roughly constant along the evolutionary tracks of early-type galaxies. The average dark matter slope is consistent with that of a Navarro-Frenk-White profile, but is not well constrained. The stellar IMF normalization is close to a Salpeter IMF at log M {sub *} = 11.5 and scales strongly with increasing stellar mass. No dependence of the IMF on redshift or stellar mass density is detected. The anti-correlation between dark matter mass and stellar mass density supports the idea of mergers being more frequent in more massive dark matter halos.« less

The V-band Empirical Mass-luminosity Relation for Main Sequence Stars

NASA Astrophysics Data System (ADS)

Xia, Fang; Fu, Yan-Ning

2010-07-01

Stellar mass is an indispensable parameter in the studies of stellar physics and stellar dynamics. On the one hand, the most reliable way to determine the stellar dynamical mass is via orbital determinations of binaries. On the other hand, however, most stellar masses have to be estimated by using the mass luminosity relation (MLR). Therefore, it is important to obtain the empirical MLR through fitting the data of stellar dynamical mass and luminosity. The effect of metallicity can make this relation disperse in the V-band, but studies show that this is mainly limited to the case when the stellar mass is less than 0.6M⊙ Recently, many relevant data have been accumulated for main sequence stars with larger masses, which make it possible to significantly improve the corresponding MLR. Using a fitting method which can reasonably assign weights to the observational data including two quantities with different dimensions, we obtain a V-band MLR based on the dynamical masses and luminosities of 203 main sequence stars. In comparison with the previous work, the improved MLR is statistically significant, and the relative error of mass estimation reaches about 5%. Therefore, our MLR is useful not only in the studies of statistical nature, but also in the studies of concrete stellar systems, such as the long-term dynamical study and the short-term positioning study of a specific multiple star system.

The V Band Empirical Mass-Luminosity Relation for Main Sequence Stars

NASA Astrophysics Data System (ADS)

Xia, F.; Fu, Y. N.

2010-01-01

Stellar mass is an indispensable parameter in the studies of stellar physics and stellar dynamics. On the one hand, the most reliable way to determine the stellar dynamical mass is via orbital determination of binaries. On the other hand, however, most stellar masses have to be estimated by using the mass-luminosity relation (MLR). Therefore, it is important to obtain the empirical MLR through fitting the data of stellar dynamical mass and luminosity. The effect of metallicity can make this relation disperse in the V-band, but studies show that this is mainly limited to the case when the stellar mass is less than 0.6M⊙. Recently, many relevant data have been accumulated for main sequence stars with larger mass, which make it possible to significantly improve the corresponding MLR. Using a fitting method which can reasonably assign weight to the observational data including two quantities with different dimensions, we obtain a V-band MLR based on the dynamical masses and luminosities of 203 main sequence stars. Compared with the previous work, the improved MLR is statistically significant, and the relative error of mass estimation reaches about 5%. Therefore, our MLR is useful not only in studies of statistical nature, but also in studies of concrete stellar systems, such as the long-term dynamical study and the short-term positioning study of a specific multiple star system.

The SL2S galaxy-scale lens sample. V. dark matter halos and stellar IMF of massive early-type galaxies out to redshift 0.8

DOE PAGES

Sonnenfeld, Alessandro; Treu, Tommaso; Marshall, Philip J.; ...

2015-02-17

Here, we investigate the cosmic evolution of the internal structure of massive early-type galaxies over half of the age of the universe. We also perform a joint lensing and stellar dynamics analysis of a sample of 81 strong lenses from the Strong Lensing Legacy Survey and Sloan ACS Lens Survey and combine the results with a hierarchical Bayesian inference method to measure the distribution of dark matter mass and stellar initial mass function (IMF) across the population of massive early-type galaxies. Lensing selection effects are taken into account. Furthermore, we found that the dark matter mass projected within the innermore » 5 kpc increases for increasing redshift, decreases for increasing stellar mass density, but is roughly constant along the evolutionary tracks of early-type galaxies. The average dark matter slope is consistent with that of a Navarro-Frenk-White profile, but is not well constrained. The stellar IMF normalization is close to a Salpeter IMF at log M * = 11.5 and scales strongly with increasing stellar mass. No dependence of the IMF on redshift or stellar mass density is detected. The anti-correlation between dark matter mass and stellar mass density supports the idea of mergers being more frequent in more massive dark matter halos.« less

Stellar Mass Versus Stellar Velocity Dispersion: Which is Better for Linking Galaxies to Their Dark Matter Halos?

NASA Astrophysics Data System (ADS)

Li, Cheng; Wang, Lixin; Jing, Y. P.

2013-01-01

It was recently suggested that compared to its stellar mass (M *), the central stellar velocity dispersion (σ*) of a galaxy might be a better indicator for its host dark matter halo mass. Here we test this hypothesis by estimating the dark matter halo mass for central galaxies in groups as a function of M * and σ*. For this we have estimated the redshift-space cross-correlation function (CCF) between the central galaxies at given M * and σ* and a reference galaxy sample, from which we determine both the projected CCF, wp (rp ), and the velocity dispersion profile. A halo mass is then obtained from the average velocity dispersion within the virial radius. At fixed M *, we find very weak or no correlation between halo mass and σ*. In contrast, strong mass dependence is clearly seen even when σ* is limited to a narrow range. Our results thus firmly demonstrate that the stellar mass of central galaxies is still a good (if not the best) indicator for dark matter halo mass, better than the stellar velocity dispersion. The dependence of galaxy clustering on σ* at fixed M *, as recently discovered by Wake et al., may be attributed to satellite galaxies, for which the tidal stripping occurring within halos has stronger effect on stellar mass than on central stellar velocity dispersion.

The Role of Stellar Feedback on the Structure of the ISM and Star Formation in Galaxies

NASA Astrophysics Data System (ADS)

Grisdale, Kearn Michael

2017-08-01

Stellar feedback refers to the injection of energy, momentum and mass into the interstellar medium (ISM) by massive stars. This feedback owes to a combination of ionising radiation, radiation pressure, stellar winds and supernovae and is likely responsible both for the inefficiency of star formation in galaxies, and the observed super-sonic turbulence of the ISM. In this thesis, I study how stellar feedback shapes the ISM thereby regulating galaxy evolution. In particular, I focus on three key questions: (i) How does stellar feedback shape the gas density distribution of the ISM? (ii) How does feedback change or influence the distribution of the kinetic energy in the ISM? and (iii) What role does feedback play in determining the star formation efficiency of giant molecular clouds (GMCs)? To answer these questions, I run high resolution (Deltax 4.6 pc) numerical simulations of three isolated galaxies, both with and without stellar feedback. I compare these simulations to observations of six galaxies from The HI Nearby Galaxy Survey (THINGS) using power spectra, and I use clump finding techniques to identify GMCs in my simulations and calculate their properties. I find that the kinetic energy power spectra in stellar feedback- regulated galaxies, regardless of the galaxy's mass and size, show scalings in excellent agreement with supersonic turbulence on scales below the thickness of the HI layer. I show that feedback influences the gas density field, and drives gas turbulence, up to large (kiloparsec) scales. This is in stark contrast to the density fields generated by large-scale gravity-only driven turbulence (i.e. without stellar feedback). Simulations with stellar feedback are able to reproduce the internal properties of GMCs such as: mass, size and velocity dispersion. Finally, I demonstrate that my simulations naturally reproduce the observed scatter (3.5-4 dex) in the star formation efficiency per free-fall time of GMCs, despite only employing a simple Schmidt star formation law. I conclude that the neutral gas content of galaxies carries signatures of stellar feedback on all scales and that stellar feedback is, therefore, key to regulating the evolution of galaxies over cosmic time.

Linkage disequilibrium at the APA insecticidal seed protein locus of common bean (Phaseolus vulgaris L.).

PubMed

Blair, Matthew W; Prieto, Sergio; Díaz, Lucy M; Buendía, Héctor F; Cardona, César

2010-04-29

An interesting seed protein family with a role in preventing insect herbivory is the multi-gene, APA family encoding the alpha-amylase inhibitor, phytohemagglutinin and arcelin proteins of common bean (Phaseolus vulgaris). Variability for this gene family exists and has been exploited to breed for insect resistance. For example, the arcelin locus has been successfully transferred from wild to cultivated common bean genotypes to provide resistance against the bruchid species Zabrotes subfasciatus although the process has been hampered by a lack of genetic tools for and understanding about the locus. In this study, we analyzed linkage disequilibrium (LD) between microsatellite markers at the APA locus and bruchid resistance in a germplasm survey of 105 resistant and susceptible genotypes and compared this with LD in other parts of the genome. Microsatellite allele diversity was found to vary with each of the eight APA-linked markers analyzed, and two markers within the APA locus were found to be diagnostic for bruchid resistance or susceptibility and for the different arcelin alleles inherited from the wild accessions. Arc1 was found to provide higher levels of resistance than Arc5 and the markers in the APA locus were highly associated with resistance showing that introgression of this gene-family from wild beans provides resistance in cultivated beans. LD around the APA locus was found to be intermediate compared to other regions of the genome and the highest LD was found within the APA locus itself for example between the markers PV-atct001 and PV-ag004. We found the APA locus to be an important genetic determinant of bruchid resistance and also found that LD existed mostly within the APA locus but not beyond it. Moderate LD was also found for some other regions of the genome perhaps related to domestication genes. The LD pattern may reflect the introgression of arcelin from the wild into the cultivated background through breeding. LD and association studies for the arcelin gene, linked genes and other members of the APA family are essential for breaking linkage drag while maintaining high levels of bruchid resistance in common bean.

Preface (for CUP)

NASA Technical Reports Server (NTRS)

Pap, Judit

1993-01-01

Study of changes in solar and stellar irradiances has been of high interest for a long time. Determining the absolute value of the luminosity of stars with different ages is a crucial question for the theory of stellar evolution and energy production in stellar interiors.

Psychosocial and behavioural factors in the regulation of weight: Self-regulation, self-efficacy and locus control.

PubMed

Menéndez-González, Lara; Orts-Cortés, María Isabel

To identify the relationship and behaviour of the variables of self-control, self-efficacy and locus control in weight regulation of obese, overweight and normal weight adults. Transversal study undertaken in the Health Centre of El Coto (Gijón) from 1st April to 30th July 2015. Subjects between 18-65 years of age with a body mass index recording within the last two years. serious medical illness, eating disorders or pregnant women. Behavioural variables: self-regulation of body weight (Inventory of self-control of body weight), perceived self-efficacy in weight regulation (Inventory of perceived self-efficacy in weight regulation) and locus control in weight regulation (Inventory of locus control in weight regulation). Anthropometric variables: weight (kg) and height (m), body mass index. One hundred and six participants were included: 32 were obese, 28 overweight and 46 normal weight. Significant differences were found between the 3 study groups for total scale of self-efficacy (F=61.77; p<.01), total scale of self-regulation (F=45.97; p<.01), internal locus control (F=13.92; p=.019), other weighty influences of locus control (F=9.21; p<.01) and random locus control (F=3.50; p=.011). The relationship between body mass index and behavioural variables of self-efficacy, self-regulation and locus control, suggests the need for healthcare professionals to include psychological factors of behaviour in any preventive action and intervention directed at weight control. Copyright © 2018 Elsevier España, S.L.U. All rights reserved.

The Soft X-Ray/Microwave Ratio of Solar and Stellar Flares and Coronae

NASA Technical Reports Server (NTRS)

Benz, A. O.; Guedel, M.

1994-01-01

We have carried out plasma diagnostics of solar flares using soft X-ray (SXR) and simultaneous microwave observations and have compared the ratio of X-ray to microwave luminosities of solar flares with various active late-type stars available in the published literature. Both the SXR low-level ('quiescent') emission from stellar coronae and the flaring emission from the Sun and stars are generally interpreted as thermal radiations of coronal plasmas. On the other hand, the microwave emission of stars and solar flares is generally attributed to an extremely hot or nonthermal population of electrons. Solar flare SXR are conventionally measured in a narrower and harder passband than the stellar sources. Observations of the GOES-2 satellite in two energy channels have been used to estimate the luminosity of solar flares as it would appear in the ROSAT satellite passband. The solar and stellar flare luminosities fit well at the lower end of the active stellar coronae. The flare SXR/microwave ratio is similar to the ratio for stellar coronae. The average ratio follows a power-law relation L(sub X) varies as L(sub R)(sup 0.73 +/- 0.03) over 10 orders of magnitude from solar microflares to RS CVn and FK Com-type coronae. Dwarf Me and Ke stars, and RS CVn stars are also compatible with a linear SXR/microwave relation, but the ratio is slightly different for each type of star. Considering the differences between solar flares, stellar flares and the various active stellar coronae, the similarity of the SXR/microwave ratios is surprising. It suggests that the energetic electrons in low-level stellar coronae observed in microwaves are related in a similar way to the coronal thermal plasma as flare electrons to the flare thermal plasma, and, consequently, that the heating mechanism of active stellar coronae is a flare-like process.

Eight luminous early-type galaxies in nearby pairs and sparse groups. I. Stellar populations spatially analysed

NASA Astrophysics Data System (ADS)

Rosa, D. A.; Milone, A. C.; Krabbe, A. C.; Rodrigues, I.

2018-06-01

We present a detailed spatial analysis of stellar populations based on long-slit optical spectra in a sample of eight luminous early-type galaxies selected from nearby sparse groups and pairs, three of them may have interaction with another galaxy of similar mass. We have spatially measured luminosity-weighted averages of age, [M/H], [Fe/H], and [α /Fe] in the sample galaxies to add empirical data relative to the influence of galaxy mass, environment, interaction, and AGN feedback in their formation and evolution. The stellar population of the individual galaxies were determined through the well-established stellar population synthesis code starlight using semi-empirical simple stellar population models. Radial variations of luminosity- weighted means of age, [M/H], [Fe/H], and [α /Fe] were quantified up to half of the effective radius of each galaxy. We found trends between representative values of age, [M/H], [α /Fe], and the nuclear stellar velocity dispersion. There are also relations between the metallicity/age gradients and the velocity dispersion. Contributions of 1-4 Gyr old stellar populations were quantified in IC 5328 and NGC 6758 as well as 4-8 Gyr old ones in NGC 5812. Extended gas is present in IC 5328, NGC 1052, NGC 1209, and NGC 6758, and the presence of a LINER is identified in all these galaxies. The regions up to one effective radius of all galaxies are basically dominated by α -enhanced metal-rich old stellar populations likely due to rapid star formation episodes that induced efficient chemical enrichment. On average, the age and [α /Fe] gradients are null and the [M/H] gradients are negative, although discordant cases were found. We found no correlation between the stellar population properties and the LINER presence as well as between the stellar properties and environment or gravitational interaction, suggesting that the influence of progenitor mass cannot be discarded in the formation and evolution of early-type galaxies.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sonnenfeld, Alessandro; Treu, Tommaso; Marshall, Philip J.

Here, we investigate the cosmic evolution of the internal structure of massive early-type galaxies over half of the age of the universe. We also perform a joint lensing and stellar dynamics analysis of a sample of 81 strong lenses from the Strong Lensing Legacy Survey and Sloan ACS Lens Survey and combine the results with a hierarchical Bayesian inference method to measure the distribution of dark matter mass and stellar initial mass function (IMF) across the population of massive early-type galaxies. Lensing selection effects are taken into account. Furthermore, we found that the dark matter mass projected within the innermore » 5 kpc increases for increasing redshift, decreases for increasing stellar mass density, but is roughly constant along the evolutionary tracks of early-type galaxies. The average dark matter slope is consistent with that of a Navarro-Frenk-White profile, but is not well constrained. The stellar IMF normalization is close to a Salpeter IMF at log M * = 11.5 and scales strongly with increasing stellar mass. No dependence of the IMF on redshift or stellar mass density is detected. The anti-correlation between dark matter mass and stellar mass density supports the idea of mergers being more frequent in more massive dark matter halos.« less

The Class of Jsolated Stars and Luminous Planetary Nebulae in old stellar populations

NASA Astrophysics Data System (ADS)

Sabach, Efrat; Soker, Noam

2018-06-01

We suggest that stars whose angular momentum (J) does not increase by a companion, star or planet, along their post-main sequence evolution have much lower mass loss rates along their giant branches. Their classification to a separate group can bring insight on their late evolution stages. We here term these Jsolated stars. We argue that the mass loss rate of Jsolated stars is poorly determined because the mass loss rate expressions on the giant branches are empirically based on samples containing stars that experience strong binary interaction, with stellar or sub-stellar companions, e.g., planetary nebula (PN) progenitors. We use our earlier claim for a low mass loss rate of asymptotic giant branch (AGB) stars that are not spun-up by a stellar or substellar companion to show that we can account for the enigmatic finding that the brightest PNe in old stellar populations reach the same luminosity as the brightest PNe in young populations. It is quite likely that the best solution to the existence of bright PNe in old stellar populations is the combination of higher AGB luminosities, as obtained in some new stellar models, and the lower mass loss rates invoked here.

The scaling relationship between baryonic mass and stellar disc size in morphologically late-type galaxies

NASA Astrophysics Data System (ADS)

Wu, Po-Feng

2018-02-01

Here I report the scaling relationship between the baryonic mass and scale-length of stellar discs for ∼1000 morphologically late-type galaxies. The baryonic mass-size relationship is a single power law R_\\ast ∝ M_b^{0.38} across ∼3 orders of magnitude in baryonic mass. The scatter in size at fixed baryonic mass is nearly constant and there are no outliers. The baryonic mass-size relationship provides a more fundamental description of the structure of the disc than the stellar mass-size relationship. The slope and the scatter of the stellar mass-size relationship can be understood in the context of the baryonic mass-size relationship. For gas-rich galaxies, the stars are no longer a good tracer for the baryons. High-baryonic-mass, gas-rich galaxies appear to be much larger at fixed stellar mass because most of the baryonic content is gas. The stellar mass-size relationship thus deviates from the power-law baryonic relationship, and the scatter increases at the low-stellar-mass end. These extremely gas-rich low-mass galaxies can be classified as ultra-diffuse galaxies based on the structure.

An Extension of the EDGES Survey: Stellar Populations in Dark Matter Halos

NASA Astrophysics Data System (ADS)

van Zee, Liese

The formation and evolution of galactic disks is one of the key questions in extragalactic astronomy today. We plan to use archival data from GALEX, Spitzer, and WISE to investigate the growth and evolution of the stellar component in a statistical sample of nearby galaxies. Data covering a broad wavelength range are critical for measurement of current star formation activity, stellar populations, and stellar distributions in nearby galaxies. In order to investigate the timescales associated with the growth of galactic disks, we will (1) investigate the structure of the underlying stellar distribution, (2) measure the ratio of current-to-past star formation activity as a function of radius, and (3) investigate the growth of the stellar disk as a function of baryon fraction and total dynamical mass. The proposed projects leverage the existing deep wide field-of-view near infrared imaging observations obtained with the Spitzer Space Telescope as part of the EDGES Survey, a Cycle 8 Exploration Science Program. The proposed analysis of multiwavelength imaging observations of a well-defined statistical sample will place strong constraints on hierarchical models of galaxy formation and evolution and will further our understanding of the stellar component of nearby galaxies.

A new method to unveil embedded stellar clusters

NASA Astrophysics Data System (ADS)

Lombardi, Marco; Lada, Charles J.; Alves, João

2017-11-01

In this paper we present a novel method to identify and characterize stellar clusters deeply embedded in a dark molecular cloud. The method is based on measuring stellar surface density in wide-field infrared images using star counting techniques. It takes advantage of the differing H-band luminosity functions (HLFs) of field stars and young stellar populations and is able to statistically associate each star in an image as a member of either the background stellar population or a young stellar population projected on or near the cloud. Moreover, the technique corrects for the effects of differential extinction toward each individual star. We have tested this method against simulations as well as observations. In particular, we have applied the method to 2MASS point sources observed in the Orion A and B complexes, and the results obtained compare very well with those obtained from deep Spitzer and Chandra observations where presence of infrared excess or X-ray emission directly determines membership status for every star. Additionally, our method also identifies unobscured clusters and a low resolution version of the Orion stellar surface density map shows clearly the relatively unobscured and diffuse OB 1a and 1b sub-groups and provides useful insights on their spatial distribution.

STELLAR ENCOUNTER RATE IN GALACTIC GLOBULAR CLUSTERS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bahramian, Arash; Heinke, Craig O.; Sivakoff, Gregory R.

2013-04-01

The high stellar densities in the cores of globular clusters cause significant stellar interactions. These stellar interactions can produce close binary mass-transferring systems involving compact objects and their progeny, such as X-ray binaries and radio millisecond pulsars. Comparing the numbers of these systems and interaction rates in different clusters drives our understanding of how cluster parameters affect the production of close binaries. In this paper we estimate stellar encounter rates ({Gamma}) for 124 Galactic globular clusters based on observational data as opposed to the methods previously employed, which assumed 'King-model' profiles for all clusters. By deprojecting cluster surface brightness profilesmore » to estimate luminosity density profiles, we treat 'King-model' and 'core-collapsed' clusters in the same way. In addition, we use Monte Carlo simulations to investigate the effects of uncertainties in various observational parameters (distance, reddening, surface brightness) on {Gamma}, producing the first catalog of globular cluster stellar encounter rates with estimated errors. Comparing our results with published observations of likely products of stellar interactions (numbers of X-ray binaries, numbers of radio millisecond pulsars, and {gamma}-ray luminosity) we find both clear correlations and some differences with published results.« less

Blue Stragglers in Clusters and Integrated Spectral Properties of Stellar Populations

NASA Astrophysics Data System (ADS)

Xin, Yu; Deng, Licai

Blue straggler stars are the most prominent bright objects in the colour-magnitude diagram of a star cluster that challenges the theory of stellar evolution. Star clusters are the closest counterparts of the theoretical concept of simple stellar populations (SSPs) in the Universe. SSPs are widely used as the basic building blocks to interpret stellar contents in galaxies. The concept of an SSP is a group of coeval stars which follows a given distribution in mass, and has the same chemical property and age. In practice, SSPs are more conveniently made by the latest stellar evolutionary models of single stars. In reality, however, stars can be more complicated than just single either at birth time or during the course of evolution in a typical environment. Observations of star clusters show that there are always exotic objects which do not follow the predictions of standard theory of stellar evolution. Blue straggler stars (BSSs), as discussed intensively in this book both observationally and theoretically, are very important in our context when considering the integrated spectral properties of a cluster, or a simple stellar population. In this chapter, we are going to describe how important the contribution of BSSs is to the total light of a cluster.

Stellar mass buildup in galaxies in the first 1.5 Gyr of the universe

NASA Astrophysics Data System (ADS)

Gonzalez, Valentino

In this thesis we have made extensive use of the deepest optical and infrared images currently available from the Hubble Space Telescope (HST) and the Spitzer Space Telescope to study the properties of the stellar populations and the stellar mass buildup in galaxies in the first 1.5 Gyr after the Big Bang. The star formation Rates (SFRs) estimated for LBGs at z ≳ 4 are generally in the range 1 -- 100 M⊙ yr--1. The stellar mass estimates are most robust for sources with good Spitzer/IRAC detections, corresponding to galaxies with stellar masses ≳ 108.5 M⊙ at z ˜ 4 ( ≳ 109.5 M⊙ at z ˜ 7). For sources with lower rest-frame optical luminosities, that, as a result, are individually undetected in IRAC, their average stellar masses have been studied in a stacking analysis of a large number of sources. This enables us to reach stellar masses ˜ 10 7.8 M⊙ at z ˜ 4. The stellar masses show a fairly tight correlation with UV luminosity or SFR, and the zeropoint of the relation does not seem to evolve strongly with redshift. We have taken advantage of the UV luminosity vs. stellar mass relation observed in LBGs at z ≳ 4 -- 7 to derive the stellar mass function (SMF) of galaxies at these redshifts. The method uses a combination of the UV LF and the mean UV vs. stellar mass relation (including the scatter, estimated to be ˜ 0.5 dex at bright luminosities at z ˜ 4). This method allows an analytic estimate of the low mass slope of the SMF. This slope (the power-law exponent of the SMF at low masses), is estimated to be in the --1.44 -- --1.55, range which is flatter than the UV LF faint end slope at these redshifts ( ≲ --1.74). This means that low mass systems contribute less to the total stellar mass density (SMD) of the Universe than would have been estimated assuming a constant mass-to-UV-light ratio. We show that this is also much flatter than the theoretical predictions from simulations, which generally over-predict the number density of low mass systems at these redshifts. The UV luminosity vs. stellar mass relation indicates only a small variation of the mass-to-light ratio as a function of UV luminosity. This is confirmed in a stacking analysis of a large number of sources from the HUDF and the Early Release Science fields (˜ 400 z ˜ 4, ˜ 120 z ˜ 5, ˜ 60 z ˜ 6, 36 at z ˜ 7). Interestingly, the stacked SEDs at z ≳ 5 in the rest-frame optical shows a color [3.6] -- [4.5] ˜ 0.3 mag. This color is hard to reproduce by synthetic stellar population models that only include stellar continua, and it probably indicates the presence of moderately strong emission lines (Halpha EWrest ˜ 300 A). The contribution from such emission lines in the IRAC fluxes indicates that the stellar masses and ages could both be over-estimated by a factor ˜ 2. One of the most interesting results presented in this thesis is the apparent plateau of the specific SFR (sSFR = SFR / stellar mass). In early results, the similarity in the SEDs of galaxies at a given UV luminosity in the z ˜ 4 -- 7 redshift range resulted in very similar estimates of the SFR and stellar masses of these galaxies. Furthermore, we find that the reported sSFR estimates at z ˜ 2 are also very similar to the ones in the z ˜ 4 -- 7 redshift range (˜ 2 Gyr--1 for ˜ 5 x 109 M⊙ galaxies). A puzzle arises from the fact that the dark matter accretion rate onto halos is predicted to decrease monotonically and rather fast as a function of cosmic time (approximately ∝ (1 + z) 2.5). If gas and star formation follow the inflow of dark matter, the sSFR at a constant mass should also decrease monotonically with time, which is contrary to the indication from these observations. When we include the possible effects of emission lines, the stellar masses decrease by a factor ˜ 2x at z ≳ 5. The revised stellar masses may favor a slowly rising sSFR at z ≳ 2, but the rise as a function of redshift is still much slower (sSFR(z) ∝ (1 + z)0.7) than that of specific dark matter accretion rate. This suggests that the stellar mass buildup is somehow decoupled from the dark matter buildup at early times. (Abstract shortened by UMI.)

Relationship of Personality and Locus of Control With Employment Outcomes among Participants with Spinal Cord Injury

ERIC Educational Resources Information Center

Krause, James S.; Broderick, Lynne

2006-01-01

We investigated relationships among personality, locus of control, and current post-injury employment status for 1,391 participants with spinal cord injury. Participants with higher internality locus-of-control scores and activity scores (personality) reported more favorable employment outcomes. Higher scores on chance and powerful others (locus…

Locus of Semantic Interference in Picture Naming: Evidence from Dual-Task Performance

ERIC Educational Resources Information Center

Piai, Vitória; Roelofs, Ardi; Schriefers, Herbert

2014-01-01

Disagreement exists regarding the functional locus of semantic interference of distractor words in picture naming. This effect is a cornerstone of modern psycholinguistic models of word production, which assume that it arises in lexical response-selection. However, recent evidence from studies of dual-task performance suggests a locus in…

Development of Locus of Control: A Review and Model for Further Exploration.

ERIC Educational Resources Information Center

Olejnik, Anthony B.

This paper applies a developmental perspective to locus of control studies. Contingency awareness established during infancy and early childhood is viewed as the basis for the development of locus of control expectancies. Expectancies of contingent reinforcement involve a cognitive component and can be viewed in Piagetian terms as the development…

Social Self-Efficacy, Academic Locus of Control, and Internet Addiction

ERIC Educational Resources Information Center

Iskender, Murat; Akin, Ahmet

2010-01-01

The purpose of this research is to examine the relationship of internet addiction, social self-efficacy, and academic locus of control. Participants were 311 university students who completed a questionnaire package that included the Online Cognition Scale, the Academic Locus of Control Scale, and the Perceived Social Self-efficacy Scale. The…

Health Locus of Control and Preventive Behaviour among Students of Music

ERIC Educational Resources Information Center

Spahn, Claudia; Burger, Thorsten; Hildebrandt, Horst; Seidenglanz, Karin

2005-01-01

The present study investigated health locus of control, preventive behaviour and previous playing-related health problems of music students; 326 students of music (58% female, mean age 22 years) filled in the Locus of Control Inventory for Illness and Health (Lohaus and Schmitt, 1989) and the Epidemiological Questionnaire for Musicians (Spahn,…

Criterion-Related Validity of the Nowicki-Strickland Locus of Control Scale with Academic Achievement.

ERIC Educational Resources Information Center

Nunn, Gary D.; And Others

1986-01-01

Investigated the relationships between student locus of control and academic achievement in grades five through eight. The Nowicki-Strickland Locus of Control Scale (NSLOCS) was used to measure motivation, and the Iowa Tests of Basic Skills (ITBS) to assess academic achievement. Results indicated moderate inverse relationships between level of…

Evolution and homoplasy at the Bem6 microsatellite locus in three sweetpotato whitefly (Bemisia tabaci) cryptic species

USDA-ARS?s Scientific Manuscript database

The evolution of individual microsatellite loci is often complex and homoplasy is common but often goes undetected. Sequencing alleles at a microsatellite locus can provide a more complete picture of the common evolutionary mechanisms occurring at that locus and can reveal cases of homoplasy. Within...

Evolution and homoplasy at the bem6 microsatellite locus in three Bemisia tabaci cryptic species

USDA-ARS?s Scientific Manuscript database

The evolution of individual microsatellite loci is often complex and homoplasy is common but often goes undetected. Sequencing alleles at a microsatellite locus can provide a more complete picture of the common evolutionary mechanisms occurring at that locus and can reveal cases of homoplasy. Within...

Competitiveness: relations with GPA, locus of control, sex, and athletic status.

PubMed

Frederick, C M

2000-04-01

A sample of college students and college athletes completed measures of competitiveness and locus of control. In addition, self-reports of GPA and sex were provided. Negative correlations among scores on competitiveness, GPA, and scores on internal locus of control were significant. Also, there were sex and athletic status differences in competitiveness.

The Relationship of Locus of Control and Attribution to Depression.

ERIC Educational Resources Information Center

Banks, L. Morgan, III; Goggin, William C.

Both external locus of control (i.e., a generalized expectancy that reinforcement is controlled by luck or fate instead of oneself) and internal locus of attribution (i.e., beliefs that success or failure result from an individual's actions rather than external causes) have been related to depression. To examine the relationship of attributions…

Changing Locus of Control: Steelworkers Adjusting to Forced Unemployment

ERIC Educational Resources Information Center

Legerski, Elizabeth Miklya; Cornwall, Marie; O'Neil, Brock

2006-01-01

Using an abbreviated version of Levenson's (1981) locus of control scale, we examine change over time in the locus of control of displaced steelworkers. The first data collection occurred approximately six months after plant shutdown, the second occurred a year later. Utilizing a multidimensional measurement model, we test the major assumption…

Genetic architecture and evolution of the S locus supergene in Primula vulgaris.

PubMed

Li, Jinhong; Cocker, Jonathan M; Wright, Jonathan; Webster, Margaret A; McMullan, Mark; Dyer, Sarah; Swarbreck, David; Caccamo, Mario; Oosterhout, Cock van; Gilmartin, Philip M

2016-12-02

Darwin's studies on heterostyly in Primula described two floral morphs, pin and thrum, with reciprocal anther and stigma heights that promote insect-mediated cross-pollination. This key innovation evolved independently in several angiosperm families. Subsequent studies on heterostyly in Primula contributed to the foundation of modern genetic theory and the neo-Darwinian synthesis. The established genetic model for Primula heterostyly involves a diallelic S locus comprising several genes, with rare recombination events that result in self-fertile homostyle flowers with anthers and stigma at the same height. Here we reveal the S locus supergene as a tightly linked cluster of thrum-specific genes that are absent in pins. We show that thrums are hemizygous not heterozygous for the S locus, which suggests that homostyles do not arise by recombination between S locus haplotypes as previously proposed. Duplication of a floral homeotic gene 51.7 million years (Myr) ago, followed by its neofunctionalization, created the current S locus assemblage which led to floral heteromorphy in Primula. Our findings provide new insights into the structure, function and evolution of this archetypal supergene.

Locus of Control or Self-Esteem; Which One is the Best Predictor of Academic Achievement in Iranian College Students

PubMed Central

Hosseini, Seyyed Nasrollah; Mirzaei Alavijeh, Mehdi; Karami Matin, Behzad; Hamzeh, Behrooz; Ashtarian, Hossein; Jalilian, Farzad

2016-01-01

Background Self-esteem and behavioral consequences, which are due to external or internal locus of control, are effective on academic achievement of students. Objectives The aim of this study was to determine the prediction of locus of control and self-esteem in academic achievement among the students. Materials and Methods This cross-sectional study was conducted on 300 college students in Kermanshah University of Medical Sciences in 2014. Data collection tools were in three sections: demographic, Rotter internal-external locus of control scale and Coopersmith self-esteem inventory. Data were analyzed using the SPSS software version 21. Results Results showed that 29.8% and 76.2% of the participants had internal locus of control, and high self-esteem, respectively. There was a significant correlation between self-esteem, locus of control and academic achievement of the students. Self-esteem accounted for 39.5% of the variation in academic achievement. Conclusions It seems that interventions to increase self-esteem among student can help improve academic achievement among them. PMID:27284277

PRC2 is required to maintain expression of the maternal Gtl2-Rian-Mirg locus by preventing de novo DNA methylation in mouse embryonic stem cells

PubMed Central

Das, Partha Pratim; Hendrix, David A.; Apostolou, Effie; Buchner, Alice H.; Canver, Matthew C.; Beyaz, Semir; Ljuboja, Damir; Kuintzle, Rachael; Kim, Woojin; Karnik, Rahul; Shao, Zhen; Xie, Huafeng; Xu, Jian; De Los Angeles, Alejandro; Zhang, Yingying; Choe, Junho; Jun, Don Leong Jia; Shen, Xiaohua; Gregory, Richard I.; Daley, George Q.; Meissner, Alexander; Kellis, Manolis; Hochedlinger, Konrad; Kim, Jonghwan; Orkin, Stuart H.

2017-01-01

SUMMARY Polycomb Repressive Complex 2 (PRC2) function and DNA methylation (DNAme) are typically correlated with the gene repression. Here, we show that PRC2 is required to maintain expression of maternal microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) from the Gtl2-Rian-Mirg locus, which is essential for full pluripotency of iPSCs. In the absence of PRC2 the entire locus becomes transcriptionally repressed due to gain of DNA methylation at the intergenic differentially methylated regions (IG-DMR). Furthermore, we demonstrate that the IG-DMR serves as an enhancer of the maternal Gtl2-Rian-Mirg locus. Mechanistic study reveals that PRC2 interacts physically with Dnmt3 methyltransferases and prevents their recruitment and subsequent DNAme at the IG-DMR, thereby allowing for proper expression of the maternal Gtl2-Rian-Mirg locus. Our observations provide a novel mechanism by which PRC2 counteracts the action of Dnmt3 methyltransferases at an imprinted locus required for full pluripotency. PMID:26299972

[The assessment of the level of coping style and health locus of control in patients with coronary heart disease and hypertension].

PubMed

Opuchlik, Katarzyna; Wrzesińska, Magdalena; Kocur, Józef

2009-01-01

The assessment of the level of coping style and health locus of control in patients with coronary heart disease and hypertension. The sample studied consisted of 112 patients (81 M, 31 F) at the age of 35-65 years. Two groups participated in the study; first with coronary heart disease and hypertension and second with hypertension without other diseases. The Coping Inventory for Stressful Situation and Multidimensional Health Locus of Control Scale were used in the study. Two groups of patients used the most frequent task-oriented coping style. The significant differences were seen between groups in the external health locus of control (t = 2.113; p < 0.05); patients with coronary heart disease and hypertension revealed the strongest conviction that their health depended on other people. Patients with coronary heart disease and hypertension choose the task-oriented coping style. Patients with hypertension declare for internal health locus of control. Patients with coronary heart disease and hypertension declare for external locus of control.

How does locus of control and inflated sense of responsibility relate to obsessive-compulsive symptoms in Turkish adolescents?

PubMed

Altin, Müjgan; Karanci, A Nuray

2008-12-01

This study aimed to examine the effects of responsibility attitudes, locus of control and their interactions on the general obsessive-compulsive (OC) symptomatology and the dimensions of OC symptoms in a sample of Turkish adolescents (n=385), their ages varied from 16 to 20 with a mean of 17.23 (S.D.=.68). The results of the present study revealed a significantly positive relationship between responsibility attitudes and general OC symptomatology. However, locus of control did not appear as a significant predictor of general OC symptomatology. Furthermore, results revealed that there was a significant interaction effect of responsibility attitudes with locus of control on OC symptomatology. That is, an inflated sense of responsibility and the presence of an external locus of control produced the highest level of OC symptoms. Related to the dimensions of OC symptoms, responsibility was a weak predictor of obsessive thinking symptoms, and a moderate predictor of cleanliness and checking symptoms. Locus of control and its interaction with responsibility attitudes only significantly predicted obsessional thinking symptoms.

Inferring Demographic History Using Two-Locus Statistics.

PubMed

Ragsdale, Aaron P; Gutenkunst, Ryan N

2017-06-01

Population demographic history may be learned from contemporary genetic variation data. Methods based on aggregating the statistics of many single loci into an allele frequency spectrum (AFS) have proven powerful, but such methods ignore potentially informative patterns of linkage disequilibrium (LD) between neighboring loci. To leverage such patterns, we developed a composite-likelihood framework for inferring demographic history from aggregated statistics of pairs of loci. Using this framework, we show that two-locus statistics are more sensitive to demographic history than single-locus statistics such as the AFS. In particular, two-locus statistics escape the notorious confounding of depth and duration of a bottleneck, and they provide a means to estimate effective population size based on the recombination rather than mutation rate. We applied our approach to a Zambian population of Drosophila melanogaster Notably, using both single- and two-locus statistics, we inferred a substantially lower ancestral effective population size than previous works and did not infer a bottleneck history. Together, our results demonstrate the broad potential for two-locus statistics to enable powerful population genetic inference. Copyright © 2017 by the Genetics Society of America.

The birth of gravitational evolutionary dynamics of stellar systems (from Th. Wright to W. Herschel).

NASA Astrophysics Data System (ADS)

Eremeeva, A. J.

1995-05-01

Th. Wright, I. Kant and I. H. Lambert used well-known ideas about the structure and dynamics of the Solar system as a basis of their concepts of the stellar Universe. W. Herschel discovered the main features of the true, non-hierarchical large-scale structure of the Universe. He was also a pioneer of stellar dynamics with its new statistical laws and also of the theory of dynamical evolution in stellar systems at different scales.

Exploring the Solar System with Stellar Occultations

NASA Technical Reports Server (NTRS)

Elliot, J. L.; Dunham, E. W.

1984-01-01

By recording the light intensity as a function of time when a planet occults a relatively bright star, the thermal structure of the upper atmosphere of the planet can be probed. The main feature of stellar occultation observations is their high spatial resolution, typically several thousand times better than the resolution achievable with ground-based imaging. Five stellar occultations have been observed. The main results of these observations are summarized. Stellar occultations have been observed on Uranus, Mars, Pallas, Neptune and the Jovian Ring.

CCFpams: Atmospheric stellar parameters from cross-correlation functions

NASA Astrophysics Data System (ADS)

Malavolta, Luca; Lovis, Christophe; Pepe, Francesco; Sneden, Christopher; Udry, Stephane

2017-07-01

CCFpams allows the measurement of stellar temperature, metallicity and gravity within a few seconds and in a completely automated fashion. Rather than performing comparisons with spectral libraries, the technique is based on the determination of several cross-correlation functions (CCFs) obtained by including spectral features with different sensitivity to the photospheric parameters. Literature stellar parameters of high signal-to-noise (SNR) and high-resolution HARPS spectra of FGK Main Sequence stars are used to calibrate the stellar parameters as a function of CCF areas.

Frontiers of stellar evolution

NASA Technical Reports Server (NTRS)

Lambert, David L. (Editor)

1991-01-01

The present conference discusses theoretical and observational views of star formation, spectroscopic constraints on the evolution of massive stars, very low mass stars and brown dwarfs, asteroseismology, globular clusters as tests of stellar evolution, observational tests of stellar evolution, and mass loss from cool evolved giant stars. Also discussed are white dwarfs and hot subdwarfs, neutron stars and black holes, supernovae from single stars, close binaries with evolved components, accretion disks in interacting binaries, supernovae in binary systems, stellar evolution and galactic chemical evolution, and interacting binaries containing compact components.

Association in Long-Evans hooded rats of red cell 2,3-diphosphoglycerate levels with hemoglobin types.

PubMed

Brewer, G; Gilman, J; Noble, N; Crews, V

1978-08-01

Two sublines of commercially available Long-Evans hooded rats have been developed by genetic selection. These sublines have widely differing levels of erythrocyte 2,3-diphosphoglycerate (DPG) due to different alleles at a single genetic locus. In the present work, it is shown that rats from the commercial population are also polymorphic at a hemoglobin locus, probably involving two alleles of the IIIbeta-globin chain locus. Particular hemoglobin types have been found to be strongly associated with certain DPG types, not only in the high-DPG and low-DPG lines but also in the commercial population. Two explanations for this association are considered. One is a single-locus hypothesis, with hemoglobin allelic variation causing DPG variation, and the other is a two-locus hypothesis, with marked linkage disequilibrium.

Parental interest in children's education, children's self-esteem and locus of control, and later educational attainment: twenty-six year follow-up of the 1970 British Birth Cohort.

PubMed

Flouri, Eirini

2006-03-01

Few studies have investigated if mother's interest and father's interest in child's education are linked to educational attainment via their impact on child's self-esteem and locus of control. (1) To investigate (after controlling for known confounding factors) the long-term effect of mother's and father's interest in child's education at age 10 and child's locus of control and self-esteem at age 10 in educational attainment at age 26; and (2) to explore if mother's interest and father's interest in child's education are linked to child's educational attainment via their effect in increasing child's self-esteem and internal locus of control. The study used longitudinal data from sweeps of the 1970 British Cohort Study (BCS70). The initial sample was those 1,737 men and 2,033 women with valid data on age 10 self-esteem, locus of control, father's interest, mother's interest, and age 26 educational attainment. Of these, 1,326 men and 1,578 women were included in the final analysis. The birth to age 10 factors that were controlled for were birth weight, parental social class, socio-economic disadvantage, emotional/behavioural problems, cognitive ability, and mother's educational attainment. At the multivariate level, internal locus of control and mother's interest (but not self-esteem) were significantly related to educational attainment in both men and women. Father's interest was a significant predictor of educational attainment only in women. Parent's interest was not linked to educational attainment via its impact on child's self-esteem or locus of control. Self-esteem predicted educational attainment in both genders by increasing internal locus of control, and fathers' interest predicted educational attainment in men by increasing mother's involvement. Although mothers' and fathers' interest in their children's education were not linked to educational attainment via their impact on children's self-esteem or locus of control, they were significant predictors of educational attainment especially in daughters.

Examining the effect of galaxy evolution on the stellar-halo mass relation in the EAGLE simulation

NASA Astrophysics Data System (ADS)

Kulier, Andrea; Padilla, Nelson; Schaye, Joop; Crain, Robert; Schaller, Matthieu; Bower, Richard; Theuns, Tom; Paillas, Enrique

2018-01-01

The EAGLE hydrodynamical simulation was used in Matthee et al. 2016 to examine the scatter in the stellar mass-halo mass relation of central galaxies, finding that the stellar mass (M*) correlates well with the maximum circular velocity (Vmax) of the host halo, but with a substantial scatter that does not correlate significantly with other host halo properties. Here we further examine the scatter in the stellar mass-halo mass relation of central galaxies in EAGLE, its correlation with other properties, and its origin. We find that at fixed Vmax, galaxies with lower concentration have younger stellar populations, as expected from the relationship between concentration and halo assembly time. However, at fixed Vmax and halo concentration, galaxies with larger M* have younger stellar ages, so that combining the two effects, galaxies with younger stellar ages at fixed halo mass have higher stellar masses. The host halos of galaxies with larger M* at fixed Vmax and concentration also contain more gas than those with smaller stellar masses at z = 0.1, i.e. the baryon fraction of the halos is larger. There is an even stronger correlation between the scatter in M* at z = 0.1 and the scatter in the baryon fraction of the galaxy's progenitors at z ~ 1, such that the latter sets ~50% of the scatter in M* at z = 0.1. We conclude that most of the scatter between Vmax and M* at z = 0.1 is set at earlier redshifts by the scatter in the baryon fraction of halos, which in turn is primarily the result of differences in feedback strength within halos.

Galaxy structure from multiple tracers - III. Radial variations in M87's IMF

NASA Astrophysics Data System (ADS)

Oldham, Lindsay; Auger, Matthew

2018-03-01

We present the first constraints on stellar mass-to-light ratio gradients in an early-type galaxy (ETG) using multiple dynamical tracer populations to model the dark and luminous mass structure simultaneously. We combine the kinematics of the central starlight, two globular cluster populations and satellite galaxies in a Jeans analysis to obtain new constraints on M87's mass structure, employing a flexible mass model which allows for radial gradients in the stellar-mass-to-light ratio. We find that, in the context of our model, a radially declining stellar-mass-to-light ratio is strongly favoured. Modelling the stellar-mass-to-light ratio as following a power law, ϒ⋆ ˜ R-μ, we infer a power-law slope μ = -0.54 ± 0.05; equally, parametrizing the stellar-mass-to-light ratio via a central mismatch parameter relative to a Salpeter initial mass function (IMF), α, and scale radius RM, we find α > 1.48 at 95% confidence and RM = 0.35 ± 0.04 kpc. We use stellar population modelling of high-resolution 11-band HST photometry to show that such a steep gradient cannot be achieved by variations in only the metallicity, age, dust extinction and star formation history if the stellar IMF remains spatially constant. On the other hand, the stellar-mass-to-light ratio gradient that we find is consistent with an IMF whose inner slope changes such that it is Salpeter-like in the central ˜0.5 kpc and becomes Chabrier-like within the stellar effective radius. This adds to recent evidence that the non-universality of the IMF in ETGs may be confined to their core regions, and points towards a picture in which the stars in these central regions may have formed in fundamentally different physical conditions.

Gas expulsion vs gas retention in young stellar clusters II: effects of cooling and mass segregation

NASA Astrophysics Data System (ADS)

Silich, Sergiy; Tenorio-Tagle, Guillermo

2018-05-01

Gas expulsion or gas retention is a central issue in most of the models for multiple stellar populations and light element anti-correlations in globular clusters. The success of the residual matter expulsion or its retention within young stellar clusters has also a fundamental importance in order to understand how star formation proceeds in present-day and ancient star-forming galaxies and if proto-globular clusters with multiple stellar populations are formed in the present epoch. It is usually suggested that either the residual gas is rapidly ejected from star-forming clouds by stellar winds and supernova explosions, or that the enrichment of the residual gas and the formation of the second stellar generation occur so rapidly, that the negative stellar feedback is not significant. Here we continue our study of the early development of star clusters in the extreme environments and discuss the restrictions that strong radiative cooling and stellar mass segregation provide on the gas expulsion from dense star-forming clouds. A large range of physical initial conditions in star-forming clouds which include the star-forming cloud mass, compactness, gas metallicity, star formation efficiency and effects of massive stars segregation are discussed. It is shown that in sufficiently massive and compact clusters hot shocked winds around individual massive stars may cool before merging with their neighbors. This dramatically reduces the negative stellar feedback, prevents the development of the global star cluster wind and expulsion of the residual and the processed matter into the ambient interstellar medium. The critical lines which separate the gas expulsion and the gas retention regimes are obtained.

Extended Main-sequence Turn-offs in Intermediate-age Star Clusters: Stellar Rotation Diminishes, but Does Not Eliminate, Age Spreads

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goudfrooij, Paul; Correnti, Matteo; Girardi, Léo, E-mail: goudfroo@stsci.edu

Extended main-sequence turn-off (eMSTO) regions are a common feature in color–magnitude diagrams of young- and intermediate-age star clusters in the Magellanic Clouds. The nature of eMSTOs remains debated in the literature. The currently most popular scenarios are extended star formation activity and ranges of stellar rotation rates. Here we study details of differences in main-sequence turn-off (MSTO) morphology expected from spreads in age versus spreads in rotation rates, using Monte Carlo simulations with the Geneva syclist isochrone models that include the effects of stellar rotation. We confirm a recent finding of Niederhofer et al. that a distribution of stellar rotationmore » velocities yields an MSTO extent that is proportional to the cluster age, as observed. However, we find that stellar rotation yields MSTO crosscut widths that are generally smaller than observed ones at a given age. We compare the simulations with high-quality Hubble Space Telescope data of NGC 1987 and NGC 2249, which are the two only relatively massive star clusters with an age of ∼1 Gyr for which such data is available. We find that the distribution of stars across the eMSTOs of these clusters cannot be explained solely by a distribution of stellar rotation velocities, unless the orientations of rapidly rotating stars are heavily biased toward an equator-on configuration. Under the assumption of random viewing angles, stellar rotation can account for ∼60% and ∼40% of the observed FWHM widths of the eMSTOs of NGC 1987 and NGC 2249, respectively. In contrast, a combination of distributions of stellar rotation velocities and stellar ages fits the observed eMSTO morphologies very well.« less

The PAndAS Field of Streams: Stellar Structures in the Milky Way Halo toward Andromeda and Triangulum

NASA Astrophysics Data System (ADS)

Martin, Nicolas F.; Ibata, Rodrigo A.; Rich, R. Michael; Collins, Michelle L. M.; Fardal, Mark A.; Irwin, Michael J.; Lewis, Geraint F.; McConnachie, Alan W.; Babul, Arif; Bate, Nicholas F.; Chapman, Scott C.; Conn, Anthony R.; Crnojević, Denija; Ferguson, Annette M. N.; Mackey, A. Dougal; Navarro, Julio F.; Peñarrubia, Jorge; Tanvir, Nial T.; Valls-Gabaud, David

2014-05-01

We reveal the highly structured nature of the Milky Way (MW) stellar halo within the footprint of the Pan-Andromeda Archaeological Survey (PAndAS) photometric survey from blue main sequence (MS) and MS turn-off stars. We map no fewer than five stellar structures within a heliocentric range of ~5-30 kpc. Some of these are known (the Monoceros Ring, the Pisces/Triangulum globular cluster stream), but we also uncover three well-defined stellar structures that could be, at least partly, responsible for the so-called Triangulum/Andromeda and Triangulum/Andromeda 2 features. In particular, we trace a new faint stellar stream located at a heliocentric distance of ~17 kpc. With a surface brightness of Σ V ~ 32-32.5 mag arcsec-2, it follows an orbit that is almost parallel to the Galactic plane north of M31 and has so far eluded surveys of the MW halo as these tend to steer away from regions dominated by the Galactic disk. Investigating our follow-up spectroscopic observations of PAndAS, we serendipitously uncover a radial velocity signature from stars that have colors and magnitudes compatible with the stream. From the velocity of eight likely member stars, we show that this stellar structure is dynamically cold, with an unresolved velocity dispersion that is lower than 7.1 km s-1 at the 90% confidence level. Along with the width of the stream (300-650 pc), its dynamics point to a dwarf-galaxy-accretion origin. The numerous stellar structures we can map in the MW stellar halo between 5 and 30 kpc and their varying morphology is a testament to the complex nature of the stellar halo at these intermediate distances.

Habitability in Different Milky Way Stellar Environments: A Stellar Interaction Dynamical Approach

PubMed Central

Pichardo, Bárbara; Lake, George; Segura, Antígona

2013-01-01

Abstract Every Galactic environment is characterized by a stellar density and a velocity dispersion. With this information from literature, we simulated flyby encounters for several Galactic regions, numerically calculating stellar trajectories as well as orbits for particles in disks; our aim was to understand the effect of typical stellar flybys on planetary (debris) disks in the Milky Way Galaxy. For the solar neighborhood, we examined nearby stars with known distance, proper motions, and radial velocities. We found occurrence of a disturbing impact to the solar planetary disk within the next 8 Myr to be highly unlikely; perturbations to the Oort cloud seem unlikely as well. Current knowledge of the full phase space of stars in the solar neighborhood, however, is rather poor; thus we cannot rule out the existence of a star that is more likely to approach than those for which we have complete kinematic information. We studied the effect of stellar encounters on planetary orbits within the habitable zones of stars in more crowded stellar environments, such as stellar clusters. We found that in open clusters habitable zones are not readily disrupted; this is true if they evaporate in less than 108 yr. For older clusters the results may not be the same. We specifically studied the case of Messier 67, one of the oldest open clusters known, and show the effect of this environment on debris disks. We also considered the conditions in globular clusters, the Galactic nucleus, and the Galactic bulge-bar. We calculated the probability of whether Oort clouds exist in these Galactic environments. Key Words: Stellar interactions—Galactic habitable zone—Oort cloud. Astrobiology 13, 491–509. PMID:23659647

The Prospect for Detecting Stellar Coronal Mass Ejections

NASA Astrophysics Data System (ADS)

Osten, Rachel A.; Crosley, Michael Kevin

2018-06-01

The astrophysical study of mass loss, both steady-state and transient, on the cool half of the HR diagram has implications bothfor the star itself and the conditions created around the star that can be hospitable or inimical to supporting life. Recent results from exoplanet studies show that planets around M dwarfs are exceedingly common, which together with the commonality of M dwarfs in our galaxy make this the dominant mode of star and planet configurations. The closeness of the exoplanets to the parent M star motivate a comprehensive understanding of habitability for these systems. Radio observations provide the most clear signature of accelerated particles and shocks in stars arising as the result of MHD processes in the stellar outer atmosphere. Stellar coronal mass ejections have not been conclusively detected, despite the ubiquity with which their radiative counterparts in an eruptive event (stellar flares) have. I will review some of the different observational methods which have been used and possibly could be used in the future in the stellar case, emphasizing some of the difficulties inherent in such attempts. I will provide a framework for interpreting potential transient stellar mass loss in light of the properties of flares known to occur on magnetically active stars. This uses a physically motivated way to connect the properties of flares and coronal mass ejections and provides a testable hypothesis for observing or constraining transient stellar mass loss. I will describe recent results using radio observations to detect stellar coronal mass ejections, and what those results imply about transient stellar mass loss. I will provide some motivation for what could be learned in this topic from space-based low frequency radio experiments.

Observing Stellar Clusters in the Computer

NASA Astrophysics Data System (ADS)

Borch, A.; Spurzem, R.; Hurley, J.

2006-08-01

We present a new approach to combine direct N-body simulations to stellar population synthesis modeling in order to model the dynamical evolution and color evolution of globular clusters at the same time. This allows us to model the spectrum, colors and luminosities of each star in the simulated cluster. For this purpose the NBODY6++ code (Spurzem 1999) is used, which is a parallel version of the NBODY code. J. Hurley implemented simple recipes to follow the changes of stellar masses, radii, and luminosities due to stellar evolution into the NBODY6++ code (Hurley et al. 2001), in the sense that each simulation particle represents one star. These prescriptions cover all evolutionary phases and solar to globular cluster metallicities. We used the stellar parameters obtained by this stellar evolution routine and coupled them to the stellar library BaSeL 2.0 (Lejeune et al. 1997). As a first application we investigated the integrated broad band colors of simulated clusters. We modeled tidally disrupted globular clusters and compared the results with isolated globular clusters. Due to energy equipartition we expected a relative blueing of tidally disrupted clusters, because of the higher escape probability of red, low-mass stars. This behaviour we actually observe for concentrated globular clusters. The mass-to-light ratio of isolated clusters follows exactly a color-M/L correlation, similar as described in Bell and de Jong (2001) in the case of spiral galaxies. At variance to this correlation, in tidally disrupted clusters the M/L ratio becomes significantly lower at the time of cluster dissolution. Hence, for isolated clusters the behavior of the stellar population is not influenced by dynamical evolution, whereas the stellar population of tidally disrupted clusters is strongly influenced by dynamical effects.

Influence of stellar multiplicity on planet formation. I. Evidence of suppressed planet formation due to stellar companions within 20 au and validation of four planets from the Kepler multiple planet candidates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Ji; Fischer, Debra A.; Xie, Ji-Wei

2014-03-01

The planet occurrence rate for multiple stars is important in two aspects. First, almost half of stellar systems in the solar neighborhood are multiple systems. Second, the comparison of the planet occurrence rate for multiple stars to that for single stars sheds light on the influence of stellar multiplicity on planet formation and evolution. We developed a method of distinguishing planet occurrence rates for single and multiple stars. From a sample of 138 bright (K{sub P} < 13.5) Kepler multi-planet candidate systems, we compared the stellar multiplicity rate of these planet host stars to that of field stars. Using dynamicalmore » stability analyses and archival Doppler measurements, we find that the stellar multiplicity rate of planet host stars is significantly lower than field stars for semimajor axes less than 20 AU, suggesting that planet formation and evolution are suppressed by the presence of a close-in companion star at these separations. The influence of stellar multiplicity at larger separations is uncertain because of search incompleteness due to a limited Doppler observation time baseline and a lack of high-resolution imaging observation. We calculated the planet confidence for the sample of multi-planet candidates and find that the planet confidences for KOI 82.01, KOI 115.01, KOI 282.01, and KOI 1781.02 are higher than 99.7% and thus validate the planetary nature of these four planet candidates. This sample of bright Kepler multi-planet candidates with refined stellar and orbital parameters, planet confidence estimation, and nearby stellar companion identification offers a well-characterized sample for future theoretical and observational study.« less

THE STRUCTURE AND STELLAR CONTENT OF THE OUTER DISKS OF GALAXIES: A NEW VIEW FROM THE Pan-STARRS1 MEDIUM DEEP SURVEY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Zheng; Thilker, David A.; Heckman, Timothy M.

2015-02-20

We present the results of an analysis of Pan-STARRS1 Medium Deep Survey multi-band (grizy) images of a sample of 698 low-redshift disk galaxies that span broad ranges in stellar mass, star-formation rate, and bulge/disk ratio. We use population synthesis spectral energy distribution fitting techniques to explore the radial distribution of the light, color, surface mass density, mass/light ratio, and age of the stellar populations. We characterize the structure and stellar content of the galaxy disks out to radii of about twice Petrosian r {sub 90}, beyond which the halo light becomes significant. We measure normalized radial profiles for sub-samples ofmore » galaxies in three bins each of stellar mass and concentration. We also fit radial profiles to each galaxy. The majority of galaxies have down-bending radial surface brightness profiles in the bluer bands with a break radius at roughly r {sub 90}. However, they typically show single unbroken exponentials in the reddest bands and in the stellar surface mass density. We find that the mass/light ratio and stellar age radial profiles have a characteristic 'U' shape. There is a good correlation between the amplitude of the down-bend in the surface brightness profile and the rate of the increase in the M/L ratio in the outer disk. As we move from late- to early-type galaxies, the amplitude of the down-bend and the radial gradient in M/L both decrease. Our results imply a combination of stellar radial migration and suppression of recent star formation can account for the stellar populations of the outer disk.« less

A COMPARISON OF STELLAR ELEMENTAL ABUNDANCE TECHNIQUES AND MEASUREMENTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hinkel, Natalie R.; Young, Patrick A.; Pagano, Michael D.

2016-09-01

Stellar elemental abundances are important for understanding the fundamental properties of a star or stellar group, such as age and evolutionary history, as well as the composition of an orbiting planet. However, as abundance measurement techniques have progressed, there has been little standardization between individual methods and their comparisons. As a result, different stellar abundance procedures determine measurements that vary beyond the quoted error for the same elements within the same stars. The purpose of this paper is to better understand the systematic variations between methods and offer recommendations for producing more accurate results in the future. We invited amore » number of participants from around the world (Australia, Portugal, Sweden, Switzerland, and the United States) to calculate 10 element abundances (C, O, Na, Mg, Al, Si, Fe, Ni, Ba, and Eu) using the same stellar spectra for four stars (HD 361, HD 10700, HD 121504, and HD 202206). Each group produced measurements for each star using (1) their own autonomous techniques, (2) standardized stellar parameters, (3) a standardized line list, and (4) both standardized parameters and a line list. We present the resulting stellar parameters, absolute abundances, and a metric of data similarity that quantifies the homogeneity of the data. We conclude that standardization of some kind, particularly stellar parameters, improves the consistency between methods. However, because results did not converge as more free parameters were standardized, it is clear there are inherent issues within the techniques that need to be reconciled. Therefore, we encourage more conversation and transparency within the community such that stellar abundance determinations can be reproducible as well as accurate and precise.« less

The PAndAS field of streams: Stellar structures in the milky way halo toward Andromeda and Triangulum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, Nicolas F.; Ibata, Rodrigo A.; Rich, R. Michael

We reveal the highly structured nature of the Milky Way (MW) stellar halo within the footprint of the Pan-Andromeda Archaeological Survey (PAndAS) photometric survey from blue main sequence (MS) and MS turn-off stars. We map no fewer than five stellar structures within a heliocentric range of ∼5-30 kpc. Some of these are known (the Monoceros Ring, the Pisces/Triangulum globular cluster stream), but we also uncover three well-defined stellar structures that could be, at least partly, responsible for the so-called Triangulum/Andromeda and Triangulum/Andromeda 2 features. In particular, we trace a new faint stellar stream located at a heliocentric distance of ∼17more » kpc. With a surface brightness of Σ {sub V} ∼ 32-32.5 mag arcsec{sup –2}, it follows an orbit that is almost parallel to the Galactic plane north of M31 and has so far eluded surveys of the MW halo as these tend to steer away from regions dominated by the Galactic disk. Investigating our follow-up spectroscopic observations of PAndAS, we serendipitously uncover a radial velocity signature from stars that have colors and magnitudes compatible with the stream. From the velocity of eight likely member stars, we show that this stellar structure is dynamically cold, with an unresolved velocity dispersion that is lower than 7.1 km s{sup –1} at the 90% confidence level. Along with the width of the stream (300-650 pc), its dynamics point to a dwarf-galaxy-accretion origin. The numerous stellar structures we can map in the MW stellar halo between 5 and 30 kpc and their varying morphology is a testament to the complex nature of the stellar halo at these intermediate distances.« less

A direct imaging search for close stellar and sub-stellar companions to young nearby stars

NASA Astrophysics Data System (ADS)

Vogt, N.; Mugrauer, M.; Neuhäuser, R.; Schmidt, T. O. B.; Contreras-Quijada, A.; Schmidt, J. G.

2015-01-01

A total of 28 young nearby stars (ages {≤ 60} Myr) have been observed in the K_s-band with the adaptive optics imager Naos-Conica of the Very Large Telescope at the Paranal Observatory in Chile. Among the targets are ten visual binaries and one triple system at distances between 10 and 130 pc, all previously known. During a first observing epoch a total of 20 faint stellar or sub-stellar companion-candidates were detected around seven of the targets. These fields, as well as most of the stellar binaries, were re-observed with the same instrument during a second epoch, about one year later. We present the astrometric observations of all binaries. Their analysis revealed that all stellar binaries are co-moving. In two cases (HD 119022 AB and FG Aqr B/C) indications for significant orbital motions were found. However, all sub-stellar companion candidates turned out to be non-moving background objects except PZ Tel which is part of this project but whose results were published elsewhere. Detection limits were determined for all targets, and limiting masses were derived adopting three different age values; they turn out to be less than 10 Jupiter masses in most cases, well below the brown dwarf mass range. The fraction of stellar multiplicity and of the sub-stellar companion occurrence in the star forming regions in Chamaeleon are compared to the statistics of our search, and possible reasons for the observed differences are discussed. Based on observations made with ESO telescopes at Paranal Observatory under programme IDs 083.C-0150(B), 084.C-0364(A), 084.C-0364(B), 084.C-0364(C), 086.C-0600(A) and 086.C-0600(B).

The Galaxy mass function up to z =4 in the GOODS-MUSIC sample: into the epoch of formation of massive galaxies

NASA Astrophysics Data System (ADS)

Fontana, A.; Salimbeni, S.; Grazian, A.; Giallongo, E.; Pentericci, L.; Nonino, M.; Fontanot, F.; Menci, N.; Monaco, P.; Cristiani, S.; Vanzella, E.; de Santis, C.; Gallozzi, S.

2006-12-01

Aims.The goal of this work is to measure the evolution of the Galaxy Stellar Mass Function and of the resulting Stellar Mass Density up to redshift ≃4, in order to study the assembly of massive galaxies in the high redshift Universe. Methods: .We have used the GOODS-MUSIC catalog, containing 3000 Ks-selected galaxies with multi-wavelength coverage extending from the U band to the Spitzer 8 μm band, of which 27% have spectroscopic redshifts and the remaining fraction have accurate photometric redshifts. On this sample we have applied a standard fitting procedure to measure stellar masses. We compute the Galaxy Stellar Mass Function and the resulting Stellar Mass Density up to redshift ≃4, taking into proper account the biases and incompleteness effects. Results: .Within the well known trend of global decline of the Stellar Mass Density with redshift, we show that the decline of the more massive galaxies may be described by an exponential timescale of ≃6 Gyr up to z≃ 1.5, and proceeds much faster thereafter, with an exponential timescale of ≃0.6 Gyr. We also show that there is some evidence for a differential evolution of the Galaxy Stellar Mass Function, with low mass galaxies evolving faster than more massive ones up to z≃ 1{-}1.5 and that the Galaxy Stellar Mass Function remains remarkably flat (i.e. with a slope close to the local one) up to z≃ 1{-}1.3. Conclusions: .The observed behaviour of the Galaxy Stellar Mass Function is consistent with a scenario where about 50% of present-day massive galaxies formed at a vigorous rate in the epoch between redshift 4 and 1.5, followed by a milder evolution until the present-day epoch.

Testing the Universality of the Stellar IMF with Chandra and HST

NASA Technical Reports Server (NTRS)

Coulter, D. A.; Lehmer, B. D.; Eufrasio, R. T.; Kundu, A.; Maccarone, T.; Peacock, M.; Hornschemeier, A. E.; Basu-Zych, A.; Gonzalez, A. H.; Maraston, C.;

Bayesian logistic regression in detection of gene-steroid interaction for cancer at PDLIM5 locus.

PubMed

Wang, Ke-Sheng; Owusu, Daniel; Pan, Yue; Xie, Changchun

2016-06-01

The PDZ and LIM domain 5 (PDLIM5) gene may play a role in cancer, bipolar disorder, major depression, alcohol dependence and schizophrenia; however, little is known about the interaction effect of steroid and PDLIM5 gene on cancer. This study examined 47 single-nucleotide polymorphisms (SNPs) within the PDLIM5 gene in the Marshfield sample with 716 cancer patients (any diagnosed cancer, excluding minor skin cancer) and 2848 noncancer controls. Multiple logistic regression model in PLINK software was used to examine the association of each SNP with cancer. Bayesian logistic regression in PROC GENMOD in SAS statistical software, ver. 9.4 was used to detect gene- steroid interactions influencing cancer. Single marker analysis using PLINK identified 12 SNPs associated with cancer (P< 0.05); especially, SNP rs6532496 revealed the strongest association with cancer (P = 6.84 × 10⁻³); while the next best signal was rs951613 (P = 7.46 × 10⁻³). Classic logistic regression in PROC GENMOD showed that both rs6532496 and rs951613 revealed strong gene-steroid interaction effects (OR=2.18, 95% CI=1.31-3.63 with P = 2.9 × 10⁻³ for rs6532496 and OR=2.07, 95% CI=1.24-3.45 with P = 5.43 × 10⁻³ for rs951613, respectively). Results from Bayesian logistic regression showed stronger interaction effects (OR=2.26, 95% CI=1.2-3.38 for rs6532496 and OR=2.14, 95% CI=1.14-3.2 for rs951613, respectively). All the 12 SNPs associated with cancer revealed significant gene-steroid interaction effects (P < 0.05); whereas 13 SNPs showed gene-steroid interaction effects without main effect on cancer. SNP rs4634230 revealed the strongest gene-steroid interaction effect (OR=2.49, 95% CI=1.5-4.13 with P = 4.0 × 10⁻⁴ based on the classic logistic regression and OR=2.59, 95% CI=1.4-3.97 from Bayesian logistic regression; respectively). This study provides evidence of common genetic variants within the PDLIM5 gene and interactions between PLDIM5 gene polymorphisms and steroid use influencing cancer.

Evolution of an adaptive behavior and its sensory receptors promotes eye regression in blind cavefish.

PubMed

Yoshizawa, Masato; Yamamoto, Yoshiyuki; O'Quin, Kelly E; Jeffery, William R

2012-12-27

How and why animals lose eyesight during adaptation to the dark and food-limited cave environment has puzzled biologists since the time of Darwin. More recently, several different adaptive hypotheses have been proposed to explain eye degeneration based on studies in the teleost Astyanax mexicanus, which consists of blind cave-dwelling (cavefish) and sighted surface-dwelling (surface fish) forms. One of these hypotheses is that eye regression is the result of indirect selection for constructive characters that are negatively linked to eye development through the pleiotropic effects of Sonic Hedgehog (SHH) signaling. However, subsequent genetic analyses suggested that other mechanisms also contribute to eye regression in Astyanax cavefish. Here, we introduce a new approach to this problem by investigating the phenotypic and genetic relationships between a suite of non-visual constructive traits and eye regression. Using quantitative genetic analysis of crosses between surface fish, the Pachón cavefish population and their hybrid progeny, we show that the adaptive vibration attraction behavior (VAB) and its sensory receptors, superficial neuromasts (SN) specifically found within the cavefish eye orbit (EO), are genetically correlated with reduced eye size. The quantitative trait loci (QTL) for these three traits form two clusters of congruent or overlapping QTL on Astyanax linkage groups (LG) 2 and 17, but not at the shh locus on LG 13. Ablation of EO SN in cavefish demonstrated a major role for these sensory receptors in VAB expression. Furthermore, experimental induction of eye regression in surface fish via shh overexpression showed that the absence of eyes was insufficient to promote the appearance of VAB or EO SN. We conclude that natural selection for the enhancement of VAB and EO SN indirectly promotes eye regression in the Pachón cavefish population through an antagonistic relationship involving genetic linkage or pleiotropy among the genetic factors underlying these traits. This study demonstrates a trade-off between the evolution of a non-visual sensory system and eye regression during the adaptive evolution of Astyanax to the cave environment.

DETECTING TRIAXIALITY IN THE GALACTIC DARK MATTER HALO THROUGH STELLAR KINEMATICS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rojas-Nino, Armando; Valenzuela, Octavio; Pichardo, Barbara

Assuming the dark matter halo of the Milky Way to be a non-spherical potential (i.e., triaxial, prolate, oblate), we show how the assembling process of the Milky Way halo may have left long-lasting stellar halo kinematic fossils due to the shape of the dark matter halo. In contrast with tidal streams, which are associated with recent satellite accretion events, these stellar kinematic groups will typically show inhomogeneous chemical and stellar population properties. However, they may be dominated by a single accretion event for certain mass assembling histories. If the detection of these peculiar kinematic stellar groups were confirmed, they wouldmore » be the smoking gun for the predicted triaxiality of dark halos in cosmological galaxy formation scenarios.« less

Constraining Star Formation in Old Stellar Populations from Theoretical Spectra

NASA Astrophysics Data System (ADS)

Peterson, R. C.

2007-12-01

We are calculating stellar spectra using Kurucz codes, Castelli models, and Kurucz laboratory lines plus guesses; but must first finish adjusting gf values to match stars of solar metallicity and higher. We show that even now, 1D LTE spectral calculations fit a wide range of stellar spectra (from A to K types) over 2200 Å-9000Å once gf values are set to optimize them. Moreover, weighted coadditions of spectral calculations can be constructed that match M31 globular clusters over this entire wavelength range. Both stellar and composite grids will be archived on MAST. The age-metallicity degeneracy can be broken, but only with high-quality data, and only if rare stages of stellar evolution are incorporated where necessary.

Old stellar populations. 5: Absorption feature indices for the complete LICK/IDS sample of stars

NASA Technical Reports Server (NTRS)

Worthey, Guy; Faber, S. M.; Gonzalez, J. Jesus; Burstein, D.

1994-01-01

Twenty-one optical absorption features, 11 of which have been previously defined, are automatically measured in a sample of 460 stars. Following Gorgas et al., the indices are summarized in fitting functions that give index strengths as functions of stellar temperature, gravity, and (Fe/H). This project was carried out with the purpose of predicting index strengths in the integrated light of stellar populations of different ages and metallicities, but the data should be valuable for stellar studies in the Galaxy as well. Several of the new indices appear to be promising indicators of metallicity for old stellar populations. A complete list of index data and atmospheric parameters is available in computer-readable form.

Exploring stellar evolution with gravitational-wave observations

NASA Astrophysics Data System (ADS)

Dvorkin, Irina; Uzan, Jean-Philippe; Vangioni, Elisabeth; Silk, Joseph

2018-05-01

Recent detections of gravitational waves from merging binary black holes opened new possibilities to study the evolution of massive stars and black hole formation. In particular, stellar evolution models may be constrained on the basis of the differences in the predicted distribution of black hole masses and redshifts. In this work we propose a framework that combines galaxy and stellar evolution models and use it to predict the detection rates of merging binary black holes for various stellar evolution models. We discuss the prospects of constraining the shape of the time delay distribution of merging binaries using just the observed distribution of chirp masses. Finally, we consider a generic model of primordial black hole formation and discuss the possibility of distinguishing it from stellar-origin black holes.

Evaluation of 41 Candidate Gene Variants for Obesity in the EPIC-Potsdam Cohort by Multi-Locus Stepwise Regression

PubMed Central

Knüppel, Sven; Rohde, Klaus; Meidtner, Karina; Drogan, Dagmar; Holzhütter, Hermann-Georg; Boeing, Heiner; Fisher, Eva

2013-01-01

Objective Obesity has become a leading preventable cause of morbidity and mortality in many parts of the world. It is thought to originate from multiple genetic and environmental determinants. The aim of the current study was to introduce haplotype-based multi-locus stepwise regression (MSR) as a method to investigate combinations of unlinked single nucleotide polymorphisms (SNPs) for obesity phenotypes. Methods In 2,122 healthy randomly selected men and women of the EPIC-Potsdam cohort, the association between 41 SNPs from 18 obesity-candidate genes and either body mass index (BMI, mean = 25.9 kg/m2, SD = 4.1) or waist circumference (WC, mean = 85.2 cm, SD = 12.6) was assessed. Single SNP analyses were done by using linear regression adjusted for age, sex, and other covariates. Subsequently, MSR was applied to search for the ‘best’ SNP combinations. Combinations were selected according to specific AICc and p-value criteria. Model uncertainty was accounted for by a permutation test. Results The strongest single SNP effects on BMI were found for TBC1D1 rs637797 (β = −0.33, SE = 0.13), FTO rs9939609 (β = 0.28, SE = 0.13), MC4R rs17700144 (β = 0.41, SE = 0.15), and MC4R rs10871777 (β = 0.34, SE = 0.14). All these SNPs showed similar effects on waist circumference. The two ‘best’ six-SNP combinations for BMI (global p-value = 3.45⋅10–6 and 6.82⋅10–6) showed effects ranging from −1.70 (SE = 0.34) to 0.74 kg/m2 (SE = 0.21) per allele combination. We selected two six-SNP combinations on waist circumference (global p-value = 7.80⋅10–6 and 9.76⋅10–6) with an allele combination effect of −2.96 cm (SE = 0.76) at maximum. Additional adjustment for BMI revealed 15 three-SNP combinations (global p-values ranged from 3.09⋅10–4 to 1.02⋅10–2). However, after carrying out the permutation test all SNP combinations lost significance indicating that the statistical associations might have occurred by chance. Conclusion MSR provides a tool to search for risk-related SNP combinations of common traits or diseases. However, the search process does not always find meaningful SNP combinations in a dataset. PMID:23874820

[Analysis of allele dropout at TH01 locus in paternity testing].

PubMed

Lai, Li; Shen, Xiao-li; Xue, Shi-jie; Hu, Jie

2013-10-01

To analyze allele dropout at TH01 locus in paternity testing in order to determine the accurate genotype. To use a two STR loci genotyping system to verify an abnormal genotype for the TH01 locus with PCR using specific primers, cloning and DNA sequencing. A rare allele at TH01 locus named 5.2, which was undetectable with PowerPlex 21 system, was detected with an Identifiler system. Genetic variations may result in rare alleles and loci loss. To avoid misjudgment, laboratories should have a variety of methods for detecting loci loss.

Minicourses in Astrophysics, Modular Approach, Vol. II.

ERIC Educational Resources Information Center

Illinois Univ., Chicago.

This is the second of a two-volume minicourse in astrophysics. It contains chapters on the following topics: stellar nuclear energy sources and nucleosynthesis; stellar evolution; stellar structure and its determination; and pulsars. Each chapter gives much technical discussion, mathematical treatment, diagrams, and examples. References are…

A catalog of stellar spectrophotometry

NASA Technical Reports Server (NTRS)

Adelman, S. J.; Pyper, D. M.; Shore, S. N.; White, R. E.; Warren, W. H., Jr.

1989-01-01

A machine-readable catalog of stellar spectrophotometric measurements made with rotating grating scanner is introduced. Consideration is given to the processes by which the stellar data were collected and calibrated with the fluxes of Vega (Hayes and Latham, 1975). A sample page from the spectrophotometric catalog is presented.

Revealing Stellar Surface Structure Behind Transiting Exoplanets

NASA Astrophysics Data System (ADS)

Dravins, Dainis

2018-04-01

During exoplanet transits, successive stellar surface portions become hidden and differential spectroscopy between various transit phases provide spectra of small surface segments temporarily hidden behind the planet. Line profile changes across the stellar disk offer diagnostics for hydrodynamic modeling, while exoplanet analyses require stellar background spectra to be known along the transit path. Since even giant planets cover only a small fraction of any main-sequence star, very precise observations are required, as well as averaging over numerous spectral lines with similar parameters. Spatially resolved Fe I line profiles across stellar disks have now been retrieved for HD209458 (G0V) and HD189733A (K1V), using data from the UVES and HARPS spectrometers. Free from rotational broadening, spatially resolved profiles are narrower and deeper than in integrated starlight. During transit, the profiles shift towards longer wavelengths, illustrating both stellar rotation at the latitude of transit and the prograde orbital motion of the exoplanets. This method will soon become applicable to more stars, once additional bright exoplanet hosts have been found.

Scaling Stellar Mass Estimates of Dwarf Galaxies

NASA Astrophysics Data System (ADS)

Carr, Brandon Michael; McQuinn, Kristen B.; Cannon, John M.; Dalcanton, Julianne; Dolphin, Andrew E.; Skillman, Evan D.; Williams, Benjamin F.; van Zee, Liese

2017-01-01

Hubble Space Telescope (HST) optical imaging of resolved stellar populations has been used to constrain the star formation history (SFH) and chemical evolution of many nearby dwarf galaxies. However, even for dwarf galaxies, the angle subtended by nearby systems can be greater than the HST field of view. Thus, estimates of stellar mass from the HST footprint do not accurately represent the total mass of the system, impacting how SFH results can be used in holistic comparisons of galaxy properties. Here, we use the SFHs of dwarfs combined with stellar population synthesis models to determine mass-to-light ratios for individual galaxies, and compare these values with measured infrared luminosities from Spitzer IRAC data. In this way, we determine what fraction of mass is not included in the HST field of view. To test our methodology, we focus on dwarfs whose stellar disks are contained within the HST observations. Then, we also apply this method to galaxies with larger angular sizes to scale the stellar masses accordingly.

Astronomy In Denver: Polarization of Stellar Wind Bow Shocks

NASA Astrophysics Data System (ADS)

Lin, Austin A.; Shrestha, Manisha; Wolfe, Tristan; Stencel, Robert E.; Hoffman, Jennifer L.

2018-06-01

When a star with stellar wind moves through the interstellar medium (ISM) at a relative supersonic velocity, an arch like structure known as a stellar wind bow shock is formed. Studying the characteristics of these structures can further our understanding of evolved stellar winds and the composition of the ISM. Observations of these structures have been performed for some time, but the recent discovery of many bow shock structures have opened more ways to study them. These stellar wind bow shocks display aspherical shapes, which cause light scattering through the dense shock material to become polarized. We selected a target star for observation using a catalog compiled from previous studies and observed it in polarized light with the University of Denver’s DUSTPol instrument. Our group has also simulated the polarization of stellar wind bow shocks using a Monte Carlo radiative transfer code. We present the data from our observations and compare them with the simulations. We also discuss the contribution of interstellar polarization to the data.

Abnormal behaviour of lithium in coeval stars?

NASA Astrophysics Data System (ADS)

Llorente de Andrés, F.; Morales-Durán, C.; Chavero, C.; de la Reza, R.

2015-05-01

Due to its fragility, the light element lithium (Li) is an excellent and very used indicator of stellar processes. Our interest here is to explore and try to understand the Li dispersion observed in some stellar open clusters which are not explained by the standard theories. A typical and historical case, for example, is that found for stars cooler than the stellar effective temperature Teff ˜ 5500 K in the Pleiades cluster with an age of ˜ 130 My (see details in Figure 2 of this poster). What is the mechanism that provoques this dispersion?. Up to now, mainly three mechanisms are being proposed : (1) Episodic accretion during the protostellar phase (Barafee et al. 2010). (2) Rotational stellar internal mixing shears due to a star-disk interaction (Eggenberger at al. 2012) and (3) Li depletion by an increased stellar radius (Somers et al. 2014). We will explore this problem using the rotational option (2) (Chavero et al. 2014) and also identifying stellar interlopers in some groups.

Implications of Stellar Feedback for Dynamical Modeling of the Milky Way and Dwarf Galaxies

NASA Astrophysics Data System (ADS)

Wetzel, Andrew

2018-04-01

I will present recent results on dynamical modeling of stellar populations from the FIRE cosmological zoom-in baryonic simulations of Milky Way-like and dwarf galaxies. First, I will discuss the dynamical formation of the Milky Way, including the origin of thin+thick stellar disk morphology. I also will discuss the curious origin of metal-rich stars on halo-like orbits near the Sun, as recently measured by Gaia, with new insights from FIRE simulations on stellar radial migration/heating. Next, I will discuss role of stellar feedback in generating non-equilibrium fluctuations of the gravitational potential in low-mass 'dwarf' galaxies, which can explain the origin of cores in their dark-matter density profiles. In particular, we predict significant observable effects on stellar dynamics, including radial migration, size fluctuations, and population gradients, which can provide observational tests of feedback-driven core formation. Finally, this scenario can explain the formation of newly discovered 'ultra-diffuse' galaxies.

Research at the Institute of Astronomy and Astrophysics of the Université Libre de Bruxelles

NASA Astrophysics Data System (ADS)

Karinkuzhi, Drisya; Chamel, Nicolas; Goriely, Stéphane; Jorissen, Alain; Pourbaix, Dimitri; Siess, Lionel; Van Eck, Sophie

2018-04-01

Over the years, a coherent research strategy has developed in the field of stellar physics at the Institute of Astronomy and Astrophysics (IAA). It involves observational studies (chemical composition of giant stars, binary properties, tomography of stellar atmospheres) that make use of the large ESO telescopes as well as of other major instruments. The presence of a high-resolution spectrograph on the 3.6-m Devasthal Optical Telescope (DOT) would therefore be highly beneficial to IAA research. These observations are complemented and supported by theoretical studies of mass transfer in binary systems, of standard and non-standard stellar evolution (including the modelling of stellar hydrodynamical nuclear burning for application to certain thermonuclear supernovae) and of nuclear astrophysics (a field in which IAA has been recognized for a long time as an international centre of excellence), including the theory of nucleosynthesis. IAA also addresses the end-points of stellar evolution as it is carrying out research on the compact remnants of stellar evolution of massive stars: neutron stars.

The effect of multiplicity of stellar encounters and the diffusion coefficients in a locally homogeneous three-dimensional stellar medium: Removing the classical divergence

NASA Astrophysics Data System (ADS)

Rastorguev, A. S.; Utkin, N. D.; Chumak, O. V.

2017-08-01

Agekyan's λ-factor that allows for the effect of multiplicity of stellar encounters with large impact parameters has been used for the first time to directly calculate the diffusion coefficients in the phase space of a stellar system. Simple estimates show that the cumulative effect, i.e., the total contribution of distant encounters to the change in the velocity of a test star, given the multiplicity of stellar encounters, is finite, and the logarithmic divergence inherent in the classical description of diffusion is removed, as was shown previously byKandrup using a different, more complex approach. In this case, the expressions for the diffusion coefficients, as in the classical description, contain the logarithm of the ratio of two independent quantities: the mean interparticle distance and the impact parameter of a close encounter. However, the physical meaning of this logarithmic factor changes radically: it reflects not the divergence but the presence of two characteristic length scales inherent in the stellar medium.

The make-up of stars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Asplund, Martin

2014-11-20

The chemical composition of stars contain vital clues not only about the stars themselves but also about the conditions prevailing before their births. As such, stellar spectroscopy plays a key role in contemporary astrophysics and cosmology by probing cosmic, galactic, stellar and planetary evolution. In this review I will describe the theoretical foundations of quantitative stellar spectroscopy: stellar atmosphere models and spectral line formation. I will focus mainly on more recent advances in the field, in particular the advent of realistic time-dependent, 3D, (magneto-)hydrodynamical simulations of stellar surface convection and atmospheres and non-LTE radiative transfer relevant for stars like themore » Sun. I will also discuss some particular applications of this type of modelling which have resulted in some exciting break-throughs in our understanding and with wider implications: the solar chemical composition, the chemical signatures of planet formation imprinted in stellar abundances, the cosmological Li problem(s) and where the first stars may be residing today.« less

Not-so-simple stellar populations in nearby, resolved massive star clusters

NASA Astrophysics Data System (ADS)

de Grijs, Richard; Li, Chengyuan

2018-02-01

Around the turn of the last century, star clusters of all kinds were considered ‘simple’ stellar populations. Over the past decade, this situation has changed dramatically. At the same time, star clusters are among the brightest stellar population components and, as such, they are visible out to much greater distances than individual stars, even the brightest, so that understanding the intricacies of star cluster composition and their evolution is imperative for understanding stellar populations and the evolution of galaxies as a whole. In this review of where the field has moved to in recent years, we place particular emphasis on the properties and importance of binary systems, the effects of rapid stellar rotation, and the presence of multiple populations in Magellanic Cloud star clusters across the full age range. Our most recent results imply a reverse paradigm shift, back to the old simple stellar population picture for at least some intermediate-age (˜1-3 Gyr old) star clusters, opening up exciting avenues for future research efforts.

Multi-scale, Hierarchically Nested Young Stellar Structures in LEGUS Galaxies

NASA Astrophysics Data System (ADS)

Thilker, David A.; LEGUS Team

2017-01-01

The study of star formation in galaxies has predominantly been limited to either young stellar clusters and HII regions, or much larger kpc-scale morphological features such as spiral arms. The HST Legacy ExtraGalactic UV Survey (LEGUS) provides a rare opportunity to link these scales in a diverse sample of nearby galaxies and obtain a more comprehensive understanding of their co-evolution for comparison against model predictions. We have utilized LEGUS stellar photometry to identify young, resolved stellar populations belonging to several age bins and then defined nested hierarchical structures as traced by these subsamples of stars. Analagous hierarchical structures were also defined using LEGUS catalogs of unresolved young stellar clusters. We will present our emerging results concerning the physical properties (e.g. area, star counts, stellar mass, star formation rate, ISM characteristics), occupancy statistics (e.g. clusters per substructure versus age and scale, parent/child demographics) and relation to overall galaxy morphology/mass for these building blocks of hierarchical star-forming structure.

[Health locus of control of patients in disease management programmes].

PubMed

Schnee, M; Grikscheit, F

2013-06-01

Health locus of control beliefs plays a major role in improving self-management skills of the chronically ill - a main goal in disease management programmes (DMP). This study aims at characterising participants in disease management regarding their health locus of control. Data are based on 4 cross-sectional postal surveys between spring and autumn of 2006 and 2007 within the Health Care Monitor of the Bertelsmann Foundation. Among the 6 285 respondents, 1 266 are chronically ill and not enrolled in a DMP and 327 are participating in a DMP. A high internal locus of control (HLC) occurs significantly less often in DMP patients than in normal chronically ill patients (and healthy people) controlling for age, gender and social class. With increasing age, a high internal locus of control is also significantly less likely. When comparing healthy people, the chronically ill and the DMP participants a social gradient of a high internal locus of control belief can be observed. The weaker internal and higher doctor-related external locus of control of DMP participants should be carefully observed by the physician when trying to strengthen the patients' self-management skills. Evaluators of DMP should take into account the different baselines of DMP patients and relevant control groups and incorporate these differences into the evaluation. © Georg Thieme Verlag KG Stuttgart · New York.

High-resolution mapping of the S-locus in Turnera leads to the discovery of three genes tightly associated with the S-alleles.

PubMed

Labonne, Jonathan J D; Goultiaeva, Alina; Shore, Joel S

2009-06-01

While the breeding system known as distyly has been used as a model system in genetics, and evolutionary biology for over a century, the genes determining this system remain unknown. To positionally clone genes determining distyly, a high-resolution map of the S-locus region of Turnera has been constructed using segregation data from 2,013 backcross progeny. We discovered three putative genes tightly linked with the S-locus. An N-acetyltransferase (TkNACE) flanks the S-locus at 0.35 cM while a sulfotransferase (TkST1) and a non-LTR retroelement (TsRETRO) show complete linkage to the S-locus. An assay of population samples of six species revealed that TsRETRO, initially discovered in diploid Turnera subulata, is also associated with the S-allele in tetraploid T. subulata and diploid Turnera scabra. The sulfotransferase gene shows some level of differential expression in long versus short styles, indicating it might be involved in some aspect of distyly. The complete linkage of TkST1 and TsRETRO to the S-locus suggests that both genes may reside within, or in the immediate vicinity of the S-locus. Chromosome walking has been initiated using one of the genes discovered in the present study to identify the genes determining distyly.

Atlas-Independent, Electrophysiological Mapping of the Optimal Locus of Subthalamic Deep Brain Stimulation for the Motor Symptoms of Parkinson Disease.

PubMed

Conrad, Erin C; Mossner, James M; Chou, Kelvin L; Patil, Parag G

2018-05-23

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) improves motor symptoms of Parkinson disease (PD). However, motor outcomes can be variable, perhaps due to inconsistent positioning of the active contact relative to an unknown optimal locus of stimulation. Here, we determine the optimal locus of STN stimulation in a geometrically unconstrained, mathematically precise, and atlas-independent manner, using Unified Parkinson Disease Rating Scale (UPDRS) motor outcomes and an electrophysiological neuronal stimulation model. In 20 patients with PD, we mapped motor improvement to active electrode location, relative to the individual, directly MRI-visualized STN. Our analysis included a novel, unconstrained and computational electrical-field model of neuronal activation to estimate the optimal locus of DBS. We mapped the optimal locus to a tightly defined ovoid region 0.49 mm lateral, 0.88 mm posterior, and 2.63 mm dorsal to the anatomical midpoint of the STN. On average, this locus is 11.75 lateral, 1.84 mm posterior, and 1.08 mm ventral to the mid-commissural point. Our novel, atlas-independent method reveals a single, ovoid optimal locus of stimulation in STN DBS for PD. The methodology, here applied to UPDRS and PD, is generalizable to atlas-independent mapping of other motor and non-motor effects of DBS. © 2018 S. Karger AG, Basel.

Relationship between healthy lifestyle behaviors and health locus of control and health-specific self-efficacy in university students.

PubMed

Açıkgöz Çepni, Serap; Kitiş, Yeter

2017-07-01

To investigate the relationship between the healthy lifestyle behaviors and the health locus of control and health-specific self-efficacy in university students. The study included 572 undergraduate students of a university in the central Anatolia region of Turkey. The data were collected with the General Characteristics Form, the Health-Promoting Lifestyle Profile II, the Multidimensional Health Locus of Control Scale, and the Perceived Health Competence Scale and investigated with the structural equation model. Health-specific self-efficacy was an important predictor of healthy lifestyle behaviors. The Internal health locus of control influenced the healthy lifestyle behaviors through health-specific self-efficacy. The other dimension was the Powerful Others health locus of control that affected healthy lifestyle behaviors, both directly and indirectly, through health-specific self-efficacy. There was a chance that the health locus of control had a negative effect on healthy lifestyle behaviors through self-efficacy. Health-specific self-efficacy is an important prerequisite for changes in healthy lifestyle behaviors, which supports Pender's model. The subscales of the health locus of control vary in their effects on healthy lifestyle behaviors, which partly supports Pender's model. Nurses, by using this model, can examine ways of improving these cognitive-perceptual factors and implement health education programs that are directed towards improving them in young persons. © 2016 Japan Academy of Nursing Science.

Locus of control, quality of life, anxiety, and depression among Malaysian breast cancer patients: The mediating role of uncertainty.

PubMed

Pahlevan Sharif, Saeed

2017-04-01

The main objective of this study was to investigate the mediating role of uncertainty in the relationship between locus of control with quality of life, anxiety, and depression. A descriptive and correlational survey was conducted in a private hospital in Kuala Lumpur, Malaysia. A convenience sample of 118 Malaysian breast cancer patients voluntarily participated in the study and responded to a set of questionnaires including: socio-demographic questionnaire, the short form of Locus of Control Scale, the Functional Assessment of Cancer Therapy-Breast (FACT-B), the Hospital Anxiety and Depression Scale (HADS), and the Short-Form Mishel Uncertainty in Illness Scale (SF-MUIS). The results revealed that breast cancer patients with higher internal locus of control and lower external locus of control experience a higher quality of life, lower anxiety, and lower depression. Also, uncertainty mediated the relationship between locus of control with quality of life and depression (quasi-significant). The findings indicated the need for early, targeted psychological interventions seeking to gradually shift cancer patients' locus of control from external to internal in order to improve their quality of life and reduce their depression and anxiety. Moreover, health care providers by providing relevant information to cancer patients, especially for externally oriented patients, can reduce their uncertainty which in turn would improve their quality of life. Copyright © 2017 Elsevier Ltd. All rights reserved.

Inferring probabilistic stellar rotation periods using Gaussian processes

NASA Astrophysics Data System (ADS)

Angus, Ruth; Morton, Timothy; Aigrain, Suzanne; Foreman-Mackey, Daniel; Rajpaul, Vinesh

2018-02-01

Variability in the light curves of spotted, rotating stars is often non-sinusoidal and quasi-periodic - spots move on the stellar surface and have finite lifetimes, causing stellar flux variations to slowly shift in phase. A strictly periodic sinusoid therefore cannot accurately model a rotationally modulated stellar light curve. Physical models of stellar surfaces have many drawbacks preventing effective inference, such as highly degenerate or high-dimensional parameter spaces. In this work, we test an appropriate effective model: a Gaussian Process with a quasi-periodic covariance kernel function. This highly flexible model allows sampling of the posterior probability density function of the periodic parameter, marginalizing over the other kernel hyperparameters using a Markov Chain Monte Carlo approach. To test the effectiveness of this method, we infer rotation periods from 333 simulated stellar light curves, demonstrating that the Gaussian process method produces periods that are more accurate than both a sine-fitting periodogram and an autocorrelation function method. We also demonstrate that it works well on real data, by inferring rotation periods for 275 Kepler stars with previously measured periods. We provide a table of rotation periods for these and many more, altogether 1102 Kepler objects of interest, and their posterior probability density function samples. Because this method delivers posterior probability density functions, it will enable hierarchical studies involving stellar rotation, particularly those involving population modelling, such as inferring stellar ages, obliquities in exoplanet systems, or characterizing star-planet interactions. The code used to implement this method is available online.

Limb Darkening and Planetary Transits: Testing Center-to-limb Intensity Variations and Limb-darkening Directly from Model Stellar Atmospheres

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neilson, Hilding R.; Lester, John B.; McNeil, Joseph T.

The transit method, employed by Microvariability and Oscillation of Stars ( MOST ), Kepler , and various ground-based surveys has enabled the characterization of extrasolar planets to unprecedented precision. These results are precise enough to begin to measure planet atmosphere composition, planetary oblateness, starspots, and other phenomena at the level of a few hundred parts per million. However, these results depend on our understanding of stellar limb darkening, that is, the intensity distribution across the stellar disk that is sequentially blocked as the planet transits. Typically, stellar limb darkening is assumed to be a simple parameterization with two coefficients thatmore » are derived from stellar atmosphere models or fit directly. In this work, we revisit this assumption and compute synthetic planetary-transit light curves directly from model stellar atmosphere center-to-limb intensity variations (CLIVs) using the plane-parallel Atlas and spherically symmetric SAtlas codes. We compare these light curves to those constructed using best-fit limb-darkening parameterizations. We find that adopting parametric stellar limb-darkening laws leads to systematic differences from the more geometrically realistic model stellar atmosphere CLIV of about 50–100 ppm at the transit center and up to 300 ppm at ingress/egress. While these errors are small, they are systematic, and they appear to limit the precision necessary to measure secondary effects. Our results may also have a significant impact on transit spectra.« less

Post Common Envelope Binaries as probes of M dwarf stellar wind and habitable zone radiation environments

NASA Astrophysics Data System (ADS)

Wilson, David

2017-08-01

M dwarf stars are promising targets in the search for extrasolar habitable planets, as their small size and close-in habitable zones make the detection of Earth-analog planets easier than at Solar-type stars. However, the effects of the high stellar activity of M dwarf hosts has uncertain effects on such planets, and may render them uninhabitable. Studying stellar activity at M dwarfs is hindered by a lack of measurements of high-energy radiation, flare activity and, in particular, stellar wind rates. We propose to rectify this by observing a sample of Post Common Envelope Binaries (PCEBs) with HST and XMM-Newton. PCEBs consist of an M dwarf with a white dwarf companion, which experiences the same stellar wind and radiation environment as a close-in planet. The stellar wind of the M dwarf accretes onto the otherwise pure hydrogen atmosphere white dwarf, producing metal lines detectable with ultraviolet spectroscopy. The metal lines can be used to measure accretion rates onto the white dwarf, from with we can accurately infer the stellar wind mass loss rate of the M dwarf, along with abundances of key elements. Simultaneous observations with XMM-Newton will probe X-ray flare occurrence rate and strength, in addition to coronal temperatures. Performing these measurements over twelve PCEBs will provide a sample of M dwarf stellar wind strengths, flare occurrence and X-ray/UV activity that will finally shed light on the true habitability of planets around small stars.

Introducing galactic structure finder: the multiple stellar kinematic structures of a simulated Milky Way mass galaxy

NASA Astrophysics Data System (ADS)

Obreja, Aura; Macciò, Andrea V.; Moster, Benjamin; Dutton, Aaron A.; Buck, Tobias; Wang, Gregory S. Stinson Liang

2018-04-01

We present the first results of applying Gaussian Mixture Models in the stellar kinematic space of normalized angular momentum and binding energy on NIHAO high resolution galaxies to separate the stars into multiple components. We exemplify this method using a simulated Milky Way analogue, whose stellar component hosts: thin and thick discs, classical and pseudo bulges, and a stellar halo. The properties of these stellar structures are in good agreement with observational expectations in terms of sizes, shapes and rotational support. Interestingly, the two kinematic discs show surface mass density profiles more centrally concentrated than exponentials, while the bulges and the stellar halo are purely exponential. We trace back in time the Lagrangian mass of each component separately to study their formation history. Between z ˜ 3 and the end of halo virialization, z ˜ 1.3, all components lose a fraction of their angular momentum. The classical bulge loses the most (˜95%) and the thin disc the least (˜60%). Both bulges formed their stars in-situ at high redshift, while the thin disc formed ˜98% in-situ, but with a constant SFR ˜ 1.5M⊙yr-1 over the last ˜ 11 Gyr. Accreted stars (6% of total stellar mass) are mainly incorporated to the thick disc or the stellar halo, which formed ex-situ 8% and 45% of their respective masses. Our analysis pipeline is freely available at https://github.com/aobr/gsf.

Merger-driven evolution of the effective stellar initial mass function of massive early-type galaxies

NASA Astrophysics Data System (ADS)

Sonnenfeld, Alessandro; Nipoti, Carlo; Treu, Tommaso

2017-02-01

The stellar initial mass function (IMF) of early-type galaxies is the combination of the IMF of the stellar population formed in situ and that of accreted stellar populations. Using as an observable the effective IMF αIMF, defined as the ratio between the true stellar mass of a galaxy and the stellar mass inferred assuming a Salpeter IMF, we present a theoretical model for its evolution as a result of dry mergers. We use a simple dry-merger evolution model, based on cosmological N-body simulations, together with empirically motivated prescriptions for the IMF to make predictions on how the effective IMF of massive early-type galaxies changes from z = 2 to z = 0. We find that the IMF normalization of individual galaxies becomes lighter with time. At fixed velocity dispersion, αIMF is predicted to be constant with redshift. Current dynamical constraints on the evolution of the IMF are in slight tension with this prediction, even though systematic uncertainties, including the effect of radial gradients in the IMF, prevent a conclusive statement. The correlation of αIMF with stellar mass becomes shallower with time, while the correlation between αIMF and velocity dispersion is mostly preserved by dry mergers. We also find that dry mergers can mix the dependence of the IMF on stellar mass and velocity dispersion, making it challenging to infer, from z = 0 observations of global galactic properties, what is the quantity that is originally coupled with the IMF.

Galaxies Grow Their Bulges and Black Holes in Diverse Ways

NASA Astrophysics Data System (ADS)

Bell, Eric F.; Monachesi, Antonela; Harmsen, Benjamin; de Jong, Roelof S.; Bailin, Jeremy; Radburn-Smith, David J.; D'Souza, Richard; Holwerda, Benne W.

2017-03-01

Galaxies with Milky Way-like stellar masses have a wide range of bulge and black hole masses; in turn, these correlate with other properties such as star formation history. While many processes may drive bulge formation, major and minor mergers are expected to play a crucial role. Stellar halos offer a novel and robust measurement of galactic merger history; cosmologically motivated models predict that mergers with larger satellites produce more massive, higher-metallicity stellar halos, reproducing the recently observed stellar halo metallicity-mass relation. We quantify the relationship between stellar halo mass and bulge or black hole prominence using a sample of 18 Milky Way-mass galaxies with newly available measurements of (or limits on) stellar halo properties. There is an order of magnitude range in bulge mass, and two orders of magnitude in black hole mass, at a given stellar halo mass (or, equivalently, merger history). Galaxies with low-mass bulges show a wide range of quiet merger histories, implying formation mechanisms that do not require intense merging activity. Galaxies with massive “classical” bulges and central black holes also show a wide range of merger histories. While three of these galaxies have massive stellar halos consistent with a merger origin, two do not—merging appears to have had little impact on making these two massive “classical” bulges. Such galaxies may be ideal laboratories to study massive bulge formation through pathways such as early gas-rich accretion, violent disk instabilities, or misaligned infall of gas throughout cosmic time.

Epithelial Cell Invasion and Adherence Directed by the Enterotoxigenic Escherichia coli tib Locus Is Associated with a 104-Kilodalton Outer Membrane Protein

DTIC Science & Technology

1994-08-01

probes. The organisms examined in this required for the adherence and invasion phenotypes of the tib study included Aeromonas hydrophila, Bordetella ... pertussis , locus. The position of the ibA gene within the tib locus was Campylobacter jejuni, Citrobacter freundii, Klebsiella pneu- identified by T7

The Effect of Locus of Control on Message Acceptance and Recall.

ERIC Educational Resources Information Center

Cole, Catherine A.; Singh, Surendra

Locus of control is a personality trait that influences human behavior in many situations. Internal-external control reactions to a persuasive message and the recall of the message were examined in two studies. In the first study, 35 undergraduate students' locus of control was measured using Duttweiler's Internal Control Measure. On the basis of…

Effects of Transcendental Meditation and Muscle Relaxation on Trait Anxiety, Maladjustment, Locus of Control, and Drug Use.

ERIC Educational Resources Information Center

Zuroff, David C.; Schwarz, J. Conrad

1978-01-01

Undergraduates received training in transcendental mediations (TM), training in a muscle relaxation technique, or no treatment. Measures of trait anxiety, locus of control, maladjustment, and drug use were collected before and after the treatment period. There were no differences in maladjustment, locus of control, or drug use as functions of…

Using Science Activities To Internalize Locus of Control and Influence Attitudes towards Science.

ERIC Educational Resources Information Center

Rowland, Paul McD.

This study investigated the relationships between science activities that emphasize cause-and-effect and a learner's locus of control. Pretests included the Nowicki-Strickland Abbreviated Scale 7-12 to measure locus of control, and a modification of the Test of Science Related Attitudes to measure attitudes toward science. The findings suggest…

Maternal Locus of Control and Developmental Gain Demonstrated by High Risk Infants: A Longitudinal Analysis.

ERIC Educational Resources Information Center

Maisto, Albert A.; German, Michael L.

1981-01-01

Short- and long-term effects of a parent-infant training program for biologically handicapped infants was evaluated in terms of maternal locus of control. Results indicated that maternal locus of control accounted for a substantial portion of the variance in the infants' developmental gains following the program intervention period. (Author/RH)

An Examination of Locus of Control, Epistemological Beliefs and Metacognitive Awareness in Preservice Early Childhood Teachers

ERIC Educational Resources Information Center

Bedel, Emine Ferda

2012-01-01

This study aims to explore the locus of control, epistemological beliefs and metacognitive awareness levels of preservice early childhood education teachers and to determine the interrelations among these variables. 206 teacher candidates have been asked to fill out Rotter's Internal-External Locus of Control Scale, Central Epistemological Beliefs…

Anxiety, locus of control and appraisal of air pollution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Navarro, P.L.; Simpson-Housley, P.; de Man, A.F.

1987-06-01

100 residents of Santiago de Chile took part in a study of the relationship among locus of control, trait-anxiety, and perception of air pollution. Concern over the problem of atmospheric pollution and number of antipollution measures taken was related to trait-anxiety. Locus of control was associated with variation in awareness of pollution hazard.

Locus of Control, Perceptions and Attributions of Student Teachers in Educational Situations.

ERIC Educational Resources Information Center

Kremer, Lya; Kurtz, Chaya

Student teachers' perceptions of locus of control was investigated. Locus of control is defined as representing the extent of dependence upon inner or outer forces, the extent one is willing to invest in shaping the environment, and the perception of reinforcement as dependent upon those efforts, or upon random events. The specific questions were:…

Predictors of Parental Locus of Control in Mothers of Pre- and Early Adolescents

ERIC Educational Resources Information Center

Freed, Rachel D.; Tompson, Martha C.

2011-01-01

Parental locus of control refers to parents' perceived power and efficacy in child-rearing situations. This study explored parental locus of control and its correlates in 160 mothers of children ages 8 to 14 cross-sectionally and 1 year later. Maternal depression, maternal expressed emotion, and child internalizing and externalizing behavior were…

Personality and Locus of Control among School Children

ERIC Educational Resources Information Center

Pandya, Archana A.; Jogsan, Yogesh A.

2013-01-01

The main purpose of this investigation is to find out the sex differences in personality traits and locus of control among school children. A total 60 children (30 boys and 30 girls) were taken as a sample. The research tool for personality, children personality questionnaire was used, which was made by Cattell and Porter. Locus of control was…

Metacognition: As a Predictor of One's Academic Locus of Control

ERIC Educational Resources Information Center

Arslan, Serhat; Akin, Ahmet

2014-01-01

The purpose of this study is to examine the effect of metacognition on one's academic locus of control. The study's sample group consists of 451 university students enrolled in various programs at Sakarya University, Turkey. In this study, the Metacognitive Awareness Inventory and the Academic Locus of Control Scale were used. The correlations and…

Childrearing and Child Development Correlates of Maternal Locus of Control.

ERIC Educational Resources Information Center

Schaefer, Earl S.; And Others

A longitudinal study tested the hypotheses that in relation to parents with an external locus of control, parents with an internal locus of control: would have a higher level of mother-infant interaction, would have more self-directing and less conforming values for children, and would have children who showed more academic competence. The initial…

Parental Efficacy and the Development of Social Competence in Young Children.

ERIC Educational Resources Information Center

Swick, Kevin J.; Hassell, Tammy

This study examined the relation of two aspects of parental efficacy (locus of control and interpersonal support) to the social competence of 62 children aged 2 to 5 years in a preschool setting. The following assessment instruments were used: Schaefer's (1979) Locus of Control Inventory to measure parental locus of control; Paul's Home Support…

Grades--Who's to Blame? Student Evaluation of Teaching and Locus of Control

ERIC Educational Resources Information Center

Grimes, Paul W.; Millea, Meghan J.; Woodruff, Thomas W.

2004-01-01

The authors examine the relationship between students' locus of control and their evaluation of teaching in a traditional principles of economics course. Locus of control is a psychological construct that identifies an individual's beliefs about the degree of personal control that can be exercised over his or her environment. Students with an…

Molecular Identification of the Schwannomatosis Locus

DTIC Science & Technology

2007-07-01

Schwannomatosis Locus PRINCIPAL INVESTIGATOR: Mia MacCollin, M.D. CONTRACTING ORGANIZATION: Massachusetts General Hospital...Identification of the Schwannomatosis Locus 5b. GRANT NUMBER DAMD17-03-1-0445 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER Mia...Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT Schwannomatosis is a recently recognized third major type of neurofibromatosis. Our

Astrophysics: An Integrative Course

ERIC Educational Resources Information Center

Gutsche, Graham D.

1975-01-01

Describes a one semester course in introductory stellar astrophysics at the advanced undergraduate level. The course aims to integrate all previously learned physics by applying it to the study of stars. After a brief introductory section on basic astronomical measurements, the main topics covered are stellar atmospheres, stellar structure, and…

77 FR 23318 - Culturally Significant Object Imported for Exhibition Determinations: “African Cosmos: Stellar Arts”

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-18

... DEPARTMENT OF STATE [Public Notice 7850] Culturally Significant Object Imported for Exhibition Determinations: ``African Cosmos: Stellar Arts'' SUMMARY: Notice is hereby given of the following determinations... the exhibition ``African Cosmos: Stellar Arts,'' imported from abroad for temporary exhibition within...

Genetic mapping of the female mimic morph locus in the ruff

PubMed Central

2013-01-01

Background Ruffs (Aves: Philomachus pugnax) possess a genetic polymorphism for male mating behaviour resulting in three permanent alternative male reproductive morphs: (i) territorial ‘Independents’, (ii) non-territorial ‘Satellites’, and (iii) female-mimicking ‘Faeders’. Development into independent or satellite morphs has previously been shown to be due to a single-locus, two-allele autosomal Mendelian mode of inheritance at the Satellite locus. Here, we use linkage analysis to map the chromosomal location of the Faeder locus, which controls development into the Faeder morph, and draw further conclusions about candidate genes, assuming shared synteny with other birds. Results Segregation data on the Faeder locus were obtained from captive-bred pedigrees comprising 64 multi-generation families (N = 381). There was no evidence that the Faeder locus was linked to the Satellite locus, but it was linked with microsatellite marker Ppu020. Comparative mapping of ruff microsatellite markers against the chicken (Gallus gallus) and zebra finch (Taeniopygia guttata) genomes places the Ppu020 and Faeder loci on a region of chromosome 11 that includes the Melanocortin-1 receptor (MC1R) gene, which regulates colour polymorphisms in numerous birds and other vertebrates. Melanin-based colouration varies with life-history strategies in ruffs and other species, thus the MC1R gene is a strong candidate to play a role in alternative male morph determination. Conclusion Two unlinked loci appear to control behavioural development in ruffs. The Faeder locus is linked to Ppu020, which, assuming synteny, is located on avian chromosome 11. MC1R is a candidate gene involved in alternative male morph determination in ruffs. PMID:24256185

Maxwell Strata and Cut Locus in the Sub-Riemannian Problem on the Engel Group

NASA Astrophysics Data System (ADS)

Ardentov, Andrei A.; Sachkov, Yuri L.

2017-12-01

We consider the nilpotent left-invariant sub-Riemannian structure on the Engel group. This structure gives a fundamental local approximation of a generic rank 2 sub-Riemannian structure on a 4-manifold near a generic point (in particular, of the kinematic models of a car with a trailer). On the other hand, this is the simplest sub-Riemannian structure of step three. We describe the global structure of the cut locus (the set of points where geodesics lose their global optimality), the Maxwell set (the set of points that admit more than one minimizer), and the intersection of the cut locus with the caustic (the set of conjugate points along all geodesics). The group of symmetries of the cut locus is described: it is generated by a one-parameter group of dilations R+ and a discrete group of reflections Z2 × Z2 × Z2. The cut locus admits a stratification with 6 three-dimensional strata, 12 two-dimensional strata, and 2 one-dimensional strata. Three-dimensional strata of the cut locus are Maxwell strata of multiplicity 2 (for each point there are 2 minimizers). Two-dimensional strata of the cut locus consist of conjugate points. Finally, one-dimensional strata are Maxwell strata of infinite multiplicity, they consist of conjugate points as well. Projections of sub-Riemannian geodesics to the 2-dimensional plane of the distribution are Euler elasticae. For each point of the cut locus, we describe the Euler elasticae corresponding to minimizers coming to this point. Finally, we describe the structure of the optimal synthesis, i. e., the set of minimizers for each terminal point in the Engel group.

Determinants of return to work after occupational injury.

PubMed

He, Yonghua; Hu, Jia; Yu, Ignatius Tak Sun; Gu, Wei; Liang, Youxin

2010-09-01

The promotion of return to work (RTW) following occupational injury benefits injured workers, their families, enterprises and the society. The identification of the potential determinants would be helpful in improving RTW rate and minimizing the duration of absenteeism following injury. The aim of the study was to identify the potential determinants of RTW following work-related injury. A historical cohort of workers with occupational injury in a state-owned locomotive vehicles company in central China was followed up on the outcomes of RTW. Demographic, employment and medical information was retrieved from the company archival documents; and post-injury information was interviewed by structured questionnaires. Univariate analysis and Cox Regression Model were used to examine the associations between potential determinants and outcomes of RTW. Three hundred of the 323 cases (92.9%) eventually returned to work after the median absence of 43 days. Factors from socio-demographic, clinical, economic, and psychological domains affected RTW in the univariate analyses. The multivariate analysis indicated that age, injury severity, injury locus, injury nature, pain in the injury locus, self-report health status and pre-injury monthly salary were significant determinants of RTW. There were multidimensional factors affecting RTW after occupational injury. Proper clinical treatment and rehabilitation, as well as economic and social support to facilitate workers' RTW would be the priorities upon intervention. Future studies should be conducted in larger representative samples to confirm the findings and to develop a multidisciplinary intervention strategy towards promoting RTW.

Association between the dopamine D3 receptor gene locus (DRD3) and unipolar affective disorder.

PubMed

Dikeos, D G; Papadimitriou, G N; Avramopoulos, D; Karadima, G; Daskalopoulou, E G; Souery, D; Mendlewicz, J; Vassilopoulos, D; Stefanis, C N

1999-12-01

Dopamine neurotransmission has been implicated in the pathophysiology of schizophrenia and, more recently, affective disorders. Among the dopamine receptors, D3 can be considered as particularly related to affective disorders due to its neuroanatomical localization in the limbic region of the brain and its relation to the serotoninergic activity of the CNS. The possible involvement of dopamine receptor D3 in unipolar (UP) major depression was investigated by a genetic association study of the D3 receptor gene locus (DRD3) on 36 UP patients and 38 ethnically matched controls. An allelic association of DRD3 (Bal I polymorphism) and UP illness was observed, with the Gly-9 allele (allele '2', 206/98 base-pairs long) being more frequent in patients than in controls (49% vs 29%, P < 0.02). The genotypes containing this allele (1-2 and 2-2) were found in 75% of patients vs 50% of controls (P < 0.03, odds ratio = 3.00, 95% CI = 1.12-8.05). The effect of the genotype remained significant (P < 0.02) after sex and family history were controlled by a multiple linear regression analysis. These results further support the hypothesis that dopaminergic mechanisms may be implicated in the pathogenesis of affective disorder. More specifically, the '2' allele of the dopamine receptor D3 gene seems to be associated with unipolar depression and can be considered as a 'phenotypic modifier' for major psychiatric disorders.

Relationships among depression during pregnancy, social support and health locus of control among Iranian pregnant women.

PubMed

Moshki, Mahdi; Cheravi, Khadijeh

2016-03-01

Prenatal depression is a significant predictor of postpartum depression and is detrimental to fetal development. To examine whether depression during pregnancy is associated with social support and health locus of control (HLC). Data were collected from a sample of 208 Iranian pregnant women using a demographic questionnaire, the Edinburgh Postnatal Depression Scale, the multidimensional HLC Scale and the social support appraisals. Depression was experienced by 37% of participants. Overall, women reported higher level of family support (6.88 ± 1.15) than other supports (6.87 ± 1.29). Protective supports from other resources (6.87 ± 1.29) were higher than those from friends (5.94 ± 1.5). Internal, powerful others and chance beliefs had the highest mean scores. Social support and chance HLC significantly influenced the proposed mediator (depressive mood) in the linear regression model. Bivariate analysis showed significant associations between social support (friend, family and others) and depressive mood. Internal HLC had a significant association with social support and powerful others HLC. However, Pearson correlation coefficient was not significant between depressive mood and all dimensions of HLC. Clinicians could assess social support and chance HLC to identify and treat women at risk of prenatal depression. By providing support during pregnancy, depression levels in women and its effects on the fetus may be decreased, which could prevent postpartum depression. © The Author(s) 2015.

Examining the candidacy of ghrelin as a gene responsible for variation in adult stature in a United Kingdom population with type 2 diabetes.

PubMed

Gueorguiev, Maria; Wiltshire, Steven; Garcia, Edwin A; Mein, Charles; Lecoeur, Cecile; Kristen, Brigitte; Allotey, Rebecca; Hattersley, Andrew T; Walker, Mark; O'rahilly, Stephen; Froguel, Philippe; Grossman, Ashley B; McCarthy, Mark I; Hitman, Graham A; Korbonits, Márta

2007-06-01

Recently, a quantitative trait locus for stature was reported on chromosome 3p26 in patients with type 2 diabetes. Given that ghrelin is a peptide involved in GH release and located on 3p26, we hypothesized that variation within its gene (GHRL) may be responsible for the quantitative trait locus on 3p26. The evidence for linkage around GHRL was refined with the genotyping of an additional four microsatellites (D3S4545, D3S1537, D3S1597, and D3S3611), giving a total of 27 markers, followed by multipoint variance components linkage analysis. Probands from the linkage families were typed for five common single nucleotide polymorphisms (SNPs) within GHRL and tested for association with adult stature using haplotype trend regression. The maximum multipoint evidence for linkage between adult stature and the 27 microsatellites yielded an LOD score of 2.58 (P = 0.0003) between D3S1297 and D3S1304. Five common (frequency of > or =5%) SNPs were typed in the probands [two promoter SNPs (rs27647 and rs26802), two exonic (rs696217 and rs4684677), and one intronic (rs35683)] capturing 80% of the total common variation in GHRL. No association was found between any SNP (or haplotypes thereof) and adult stature. Common genetic variation within GHRL is not responsible for variation in adult stature in this population.

EPIBLASTER-fast exhaustive two-locus epistasis detection strategy using graphical processing units

PubMed Central

Kam-Thong, Tony; Czamara, Darina; Tsuda, Koji; Borgwardt, Karsten; Lewis, Cathryn M; Erhardt-Lehmann, Angelika; Hemmer, Bernhard; Rieckmann, Peter; Daake, Markus; Weber, Frank; Wolf, Christiane; Ziegler, Andreas; Pütz, Benno; Holsboer, Florian; Schölkopf, Bernhard; Müller-Myhsok, Bertram

2011-01-01

Detection of epistatic interaction between loci has been postulated to provide a more in-depth understanding of the complex biological and biochemical pathways underlying human diseases. Studying the interaction between two loci is the natural progression following traditional and well-established single locus analysis. However, the added costs and time duration required for the computation involved have thus far deterred researchers from pursuing a genome-wide analysis of epistasis. In this paper, we propose a method allowing such analysis to be conducted very rapidly. The method, dubbed EPIBLASTER, is applicable to case–control studies and consists of a two-step process in which the difference in Pearson's correlation coefficients is computed between controls and cases across all possible SNP pairs as an indication of significant interaction warranting further analysis. For the subset of interactions deemed potentially significant, a second-stage analysis is performed using the likelihood ratio test from the logistic regression to obtain the P-value for the estimated coefficients of the individual effects and the interaction term. The algorithm is implemented using the parallel computational capability of commercially available graphical processing units to greatly reduce the computation time involved. In the current setup and example data sets (211 cases, 222 controls, 299468 SNPs; and 601 cases, 825 controls, 291095 SNPs), this coefficient evaluation stage can be completed in roughly 1 day. Our method allows for exhaustive and rapid detection of significant SNP pair interactions without imposing significant marginal effects of the single loci involved in the pair. PMID:21150885

The Evolution of Human Handedness

PubMed Central

McManus, I C; Davison, Angus; Armour, John A L

2013-01-01

Right- and left-handedness run in families, show greater concordance in monozygotic than dizygotic twins, and are well described by single-locus Mendelian models. Here we summarize a large genome-wide association study (GWAS) that finds no significant associations with handedness and is consistent with a meta-analysis of GWASs. The GWAS had 99% power to detect a single locus using the conventional criterion of P < 5 × 10−8 for the single locus models of McManus and Annett. The strong conclusion is that handedness is not controlled by a single genetic locus. A consideration of the genetic architecture of height, primary ciliary dyskinesia, and intelligence suggests that handedness inheritance can be explained by a multilocus variant of the McManus DC model, classical effects on family and twins being barely distinguishable from the single locus model. Based on the ENGAGE meta-analysis of GWASs, we estimate at least 40 loci are involved in determining handedness. PMID:23631511

Relationship among prospective parents' locus of control, social desirability, and choice of psychoprophylaxis.

PubMed

Windwer, C

1977-01-01

This study sought to determine if there is a relationship among locus of control, social desirability, and choice of psychoprophylaxis (PPM). It was hypothesized that internal locus of control and low social desirability would correlate significantly with the choice of PPM by husbands and wives; that externally controlled wives who participated in PPM would have more internally controlled husbands than externally controlled wives who participated in PPM would have more internally controlled husbands than externally controlled wives who did not participate; and that locus of control and social desirability, when taken together, would be better predictors of choice of PPM than either taken separately. Ninety-eight middle-class nulliparous couples, participant and non-participant, were studied in the seventh or eighth month of the wife's pregnancy. Rotter's I-E Scale and the Marlowe-Crowne Social Desirability Scale were used to measure locus of control and social desirability. Study findings did not support the hypotheses.

Perceived parenting style of fathers and adolescents' locus of control in a collectivist culture of Malaysia: the moderating role of fathers' education.

PubMed

Keshavarz, Somayeh; Baharudin, Rozumah; Mounts, Nina S

2013-01-01

The authors investigated the moderating role of father's education on the associations between perceived paternal parenting styles and locus of control among 382 Malaysian adolescents with an average age of 14.27. Data were collected by means of adolescents' self-report using standardized instruments (i.e., parental authority questionnaire and Nowicki-Strickland Internal-External Control Scale for Children). Results revealed that there were significant negative relationships between fathers' authoritative parenting style (r = -.243, p < .001) and authoritarian parenting style (r = -.130, p < .01) with adolescents' internal locus of control. Furthermore, the findings indicated that father's high level of education moderated the relationship between perceived paternal authoritarian parenting and locus of control (b = -0.147, p < .001). The findings underscore the need to include the role of parents' education when assessing the links between parenting styles and adolescents' locus of control.

A two-step process for epigenetic inheritance in Arabidopsis

PubMed Central

Blevins, Todd; Pontvianne, Frédéric; Cocklin, Ross; Podicheti, Ram; Chandrasekhara, Chinmayi; Yerneni, Satwica; Braun, Chris; Lee, Brandon; Rusch, Doug; Mockaitis, Keithanne; Tang, Haixu; Pikaard, Craig S.

2014-01-01

Summary In Arabidopsis, multisubunit RNA polymerases IV and V orchestrate RNA-directed DNA methylation (RdDM) and transcriptional silencing, but what identifies the loci to be silenced is unclear. We show that heritable silent locus identity at a specific subset of RdDM targets requires HISTONE DEACETYLASE 6 (HDA6) acting upstream of Pol IV recruitment and siRNA biogenesis. At these loci, epigenetic memory conferring silent locus identity is erased in hda6 mutants such that restoration of HDA6 activity cannot restore siRNA biogenesis or silencing. Silent locus identity is similarly lost in mutants for the cytosine maintenance methyltransferase, MET1. By contrast, pol IV or pol V mutants disrupt silencing without erasing silent locus identity, allowing restoration of Pol IV or Pol V function to restore silencing. Collectively, these observations indicate that silent locus specification and silencing are separable steps that together account for epigenetic inheritance of the silenced state. PMID:24657166

BiQ Analyzer HT: locus-specific analysis of DNA methylation by high-throughput bisulfite sequencing

PubMed Central

Lutsik, Pavlo; Feuerbach, Lars; Arand, Julia; Lengauer, Thomas; Walter, Jörn; Bock, Christoph

2011-01-01

Bisulfite sequencing is a widely used method for measuring DNA methylation in eukaryotic genomes. The assay provides single-base pair resolution and, given sufficient sequencing depth, its quantitative accuracy is excellent. High-throughput sequencing of bisulfite-converted DNA can be applied either genome wide or targeted to a defined set of genomic loci (e.g. using locus-specific PCR primers or DNA capture probes). Here, we describe BiQ Analyzer HT (http://biq-analyzer-ht.bioinf.mpi-inf.mpg.de/), a user-friendly software tool that supports locus-specific analysis and visualization of high-throughput bisulfite sequencing data. The software facilitates the shift from time-consuming clonal bisulfite sequencing to the more quantitative and cost-efficient use of high-throughput sequencing for studying locus-specific DNA methylation patterns. In addition, it is useful for locus-specific visualization of genome-wide bisulfite sequencing data. PMID:21565797

Intratypic variability of a tandem repeat locus within the DNA polymerase gene of human herpes simplex virus type 2.

PubMed

Sun, Yongjiang; Chan, Roy Kum Wah; Tan, Suat Hoon

2004-01-01

In this study, the irntratypic variability of a tandem repeat locus within the DNA polymerase (pol) gene of human herpes simplex virus type 2 (HSV2) was uncovered. The locus contained variable numbers of tandem dodecanucleotide (5'-GAC GAG GAC GGG-3') repetitive units. Our result showed that approximately 95% of analyzed HSV2 clinical isolates and the current GenBank HSV2 strains contained two copies of the repetitive units. From genital herpes specimens, three new HSV2 strains, which respectively contained 1, 3, and 4 copies of the repetitive units, were identified. This variable number of tandem repeat (VNTR) locus is absent in HSV1, and thus it also contributes to the intertypic variability of HSV1 and HSV2. The intratypic variability of the locus may be useful for HSV2 strain genotyping and this application is discussed.

A novel locus for dilated cardiomyopathy maps to canine chromosome 8.

PubMed

Werner, Petra; Raducha, Michael G; Prociuk, Ulana; Sleeper, Meg M; Van Winkle, Thomas J; Henthorn, Paula S

2008-06-01

Dilated cardiomyopathy (DCM), the most common form of cardiomyopathy, often leads to heart failure and sudden death. While a substantial proportion of DCMs are inherited, mutations responsible for the majority of DCMs remain unidentified. A genome-wide linkage study was performed to identify the locus responsible for an autosomal recessive inherited form of juvenile DCM (JDCM) in Portuguese water dogs using 16 families segregating the disease. Results link the JDCM locus to canine chromosome 8 with two-point and multipoint lod scores of 10.8 and 14, respectively. The locus maps to a 3.9-Mb region, with complete syntenic homology to human chromosome 14, that contains no genes or loci known to be involved in the development of any type of cardiomyopathy. This discovery of a DCM locus with a previously unknown etiology will provide a new gene to examine in human DCM patients and a model for testing therapeutic approaches for heart failure.

Genome-wide associations for milk production and somatic cell score in Holstein-Friesian cattle in Ireland

PubMed Central

2012-01-01

Background Contemporary dairy breeding goals have broadened to include, along with milk production traits, a number of non-production-related traits in an effort to improve the overall functionality of the dairy cow. Increased indirect selection for resistance to mastitis, one of the most important production-related diseases in the dairy sector, via selection for reduced somatic cell count has been part of these broadened goals. A number of genome-wide association studies have identified genetic variants associated with milk production traits and mastitis resistance, however the majority of these studies have been based on animals which were predominantly kept in confinement and fed a concentrate-based diet (i.e. high-input production systems). This genome-wide association study aims to detect associations using genotypic and phenotypic data from Irish Holstein-Friesian cattle fed predominantly grazed grass in a pasture-based production system (low-input). Results Significant associations were detected for milk yield, fat yield, protein yield, fat percentage, protein percentage and somatic cell score using separate single-locus, frequentist and multi-locus, Bayesian approaches. These associations were detected using two separate populations of Holstein-Friesian sires and cows. In total, 1,529 and 37 associations were detected in the sires using a single SNP regression and a Bayesian method, respectively. There were 103 associations in common between the sires and cows across all the traits. As well as detecting associations within known QTL regions, a number of novel associations were detected; the most notable of these was a region of chromosome 13 associated with milk yield in the population of Holstein-Friesian sires. Conclusions A total of 276 of novel SNPs were detected in the sires using a single SNP regression approach. Although obvious candidate genes may not be initially forthcoming, this study provides a preliminary framework upon which to identify the causal mechanisms underlying the various milk production traits and somatic cell score. Consequently this will deepen our understanding of how these traits are expressed. PMID:22449276

Admixture mapping of pelvic organ prolapse in African Americans from the Women’s Health Initiative Hormone Therapy trial

PubMed Central

Hartmann, Katherine E.; Aldrich, Melinda C.; Ward, Renee M.; Wu, Jennifer M.; Park, Amy J.; Graff, Mariaelisa; Qi, Lihong; Nassir, Rami; Wallace, Robert B.; O'Sullivan, Mary J.; North, Kari E.; Velez Edwards, Digna R.; Edwards, Todd L.

2017-01-01

Evidence suggests European American (EA) women have two- to five-fold increased odds of having pelvic organ prolapse (POP) when compared with African American (AA) women. However, the role of genetic ancestry in relation to POP risk is not clear. Here we evaluate the association between genetic ancestry and POP in AA women from the Women’s Health Initiative Hormone Therapy trial. Women with grade 1 or higher classification, and grade 2 or higher classification for uterine prolapse, cystocele or rectocele at baseline or during follow-up were considered to have any POP (N = 805) and moderate/severe POP (N = 156), respectively. Women with at least two pelvic exams with no indication for POP served as controls (N = 344). We performed case-only, and case-control admixture-mapping analyses using multiple logistic regression while adjusting for age, BMI, parity and global ancestry. We evaluated the association between global ancestry and POP using multiple logistic regression. European ancestry at the individual level was not associated with POP risk. Case-only and case-control local ancestry analyses identified two ancestry-specific loci that may be associated with POP. One locus (Chromosome 15q26.2) achieved empirically-estimated statistical significance and was associated with decreased POP odds (considering grade ≥2 POP) with each unit increase in European ancestry (OR: 0.35; 95% CI: 0.30, 0.57; p-value = 1.48x10-5). This region includes RGMA, a potent regulator of the BMP family of genes. The second locus (Chromosome 1q42.1-q42.3) was associated with increased POP odds with each unit increase in European ancestry (Odds ratio [OR]: 1.69; 95% confidence interval [CI]: 1.28, 2.22; p-value = 1.93x10-4). Although this region did not reach statistical significance after considering multiple comparisons, it includes potentially relevant genes including TBCE, and ACTA1. Unique non-overlapping European and African ancestry-specific susceptibility loci may be associated with increased POP risk. PMID:28582460

CREB1 is a strong genetic predictor of the variation in exercise heart rate response to regular exercise: the HERITAGE Family Study

PubMed Central

Rankinen, Tuomo; Argyropoulos, George; Rice, Treva; Rao, D.C.; Bouchard, Claude

2011-01-01

Background A genome-wide linkage scan identified a quantitative trait locus (QTL) for exercise training-induced changes in submaximal exercise (50W) heart rate (ΔHR50) on chromosome 2q33.3-q34 in the HERITAGE Family Study (N=472). Methods and Results To fine map the region, 1,450 tagSNPs were genotyped between 205 and 215 Mb on chromosome 2. The strongest evidence of association with ΔHR50 was observed with two SNPs located in the 5′ region of the cAMP responsive element binding protein 1 (CREB1) gene (rs2253206: p=1.6×10−5 and rs2360969: p=4.3×10−5). The associations remained significant (p=0.01 and p=0.023, respectively) after accounting for multiple testing. Regression modeling of the 39 most significant SNPs in the single-SNP analyses identified nine SNPs that collectively explained 20% of the ΔHR50 variance. CREB1 SNP rs2253206 had the strongest effect (5.45% of variance), followed by SNPs in the FASTKD2 (3.1%), MAP2 (2.6%), SPAG16 (2.1%), ERBB4 (3 SNPs ~1.4% each), IKZF2 (1.4%), and PARD3B (1.0%) loci. In conditional linkage analysis, six SNPs from the final regression model (CREB1, FASTKD2, MAP2, ERBB4, IKZF2, and PARD3B) accounted for the original linkage signal: the LOD score dropped from 2.10 to 0.41 after adjusting for all six SNPs. Functional studies revealed that the common allele of rs2253206 exhibits significantly (p<0.05) lower promoter activity than the minor allele. Conclusions Our data suggest that functional DNA sequence variation in the CREB1 locus is strongly associated with ΔHR50 and explains considerable proportion of the QTL variance. However, at least five additional SNPs seem to be required to fully account for the original linkage signal. PMID:20407090

The Next Generation Virgo Cluster Survey (NGVS). XXV. Fiducial Panchromatic Colors of Virgo Core Globular Clusters and Their Comparison to Model Predictions

NASA Astrophysics Data System (ADS)

Powalka, Mathieu; Lançon, Ariane; Puzia, Thomas H.; Peng, Eric W.; Liu, Chengze; Muñoz, Roberto P.; Blakeslee, John P.; Côté, Patrick; Ferrarese, Laura; Roediger, Joel; Sánchez-Janssen, Rúben; Zhang, Hongxin; Durrell, Patrick R.; Cuillandre, Jean-Charles; Duc, Pierre-Alain; Guhathakurta, Puragra; Gwyn, S. D. J.; Hudelot, Patrick; Mei, Simona; Toloba, Elisa

2016-11-01

The central region of the Virgo Cluster of galaxies contains thousands of globular clusters (GCs), an order of magnitude more than the number of clusters found in the Local Group. Relics of early star formation epochs in the universe, these GCs also provide ideal targets to test our understanding of the spectral energy distributions (SEDs) of old stellar populations. Based on photometric data from the Next Generation Virgo Cluster Survey (NGVS) and its near-infrared counterpart NGVS-IR, we select a robust sample of ≈ 2000 GCs with excellent photometry and tha span the full range of colors present in the Virgo core. The selection exploits the well-defined locus of GCs in the uiK diagram and the fact that the GCs are marginally resolved in the images. We show that the GCs define a narrow sequence in five-dimensional color space, with limited but real dispersion around the mean sequence. The comparison of these SEDs with the predictions of 11 widely used population synthesis models highlights differences between the models and also shows that no single model adequately matches the data in all colors. We discuss possible causes for some of these discrepancies. Forthcoming papers of this series will examine how best to estimate photometric metallicities in this context, and compare the Virgo GC colors with those in other environments.

Correction to Method of Establishing the Absolute Radiometric Accuracy of Remote Sensing Systems While On-orbit Using Characterized Stellar Sources

NASA Technical Reports Server (NTRS)

Bowen, Howard S.; Cunningham, Douglas M.

2007-01-01

The contents include: 1) Brief history of related events; 2) Overview of original method used to establish absolute radiometric accuracy of remote sensing instruments using stellar sources; and 3) Considerations to improve the stellar calibration approach.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lyon, J.F.; Grieger, G.; Rau, F.

The present status of stellarator experiments and recent progress in stellarator research (both experimental and theoretical) are reported by groups in the United States, the USSR, Japan, Australia, and the European Community (the Federal Republic of Germany and Spain). Experiments under construction and studies of large, next-generation stellarators are also described. 73 refs., 11 figs., 4 tabs.

50 CFR 226.202 - Critical habitat for Stellar sea lions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Critical habitat for Stellar sea lions... Critical habitat for Stellar sea lions. Steller Sea Lion (Eumetopias jubatus) (a) Alaska rookeries, haulouts, and associated areas. In Alaska, all major Steller sea lion rookeries identified in Table 1 and...

50 CFR 226.202 - Critical habitat for Stellar sea lions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 50 Wildlife and Fisheries 10 2013-10-01 2013-10-01 false Critical habitat for Stellar sea lions... Critical habitat for Stellar sea lions. Steller Sea Lion (Eumetopias jubatus) (a) Alaska rookeries, haulouts, and associated areas. In Alaska, all major Steller sea lion rookeries identified in Table 1 and...

50 CFR 226.202 - Critical habitat for Stellar sea lions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false Critical habitat for Stellar sea lions... Critical habitat for Stellar sea lions. Steller Sea Lion (Eumetopias jubatus) (a) Alaska rookeries, haulouts, and associated areas. In Alaska, all major Steller sea lion rookeries identified in Table 1 and...

50 CFR 226.202 - Critical habitat for Stellar sea lions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 50 Wildlife and Fisheries 10 2012-10-01 2012-10-01 false Critical habitat for Stellar sea lions... Critical habitat for Stellar sea lions. Steller Sea Lion (Eumetopias jubatus) (a) Alaska rookeries, haulouts, and associated areas. In Alaska, all major Steller sea lion rookeries identified in Table 1 and...

Summary of spacecraft technology, systems reliability, and tracking data acquisition

NASA Technical Reports Server (NTRS)

1973-01-01

Goddard activities are reported for 1973. An eight-year flight schedule for projected space missions is presented. Data acquired by spacecraft in the following disciplines are described: stellar ultraviolet, stellar X-rays, stellar gamma rays, solar radiation, radio astronomy, particles/fields, magnetosphere, aurora, and the upper atmosphere.

Stellar Populations in BL Lac type Objects

NASA Astrophysics Data System (ADS)

Serote Roos, Margarida

The relationship between an Active Galactic Nucleus (AGN) and its host galaxy is a crucial question in the study of galaxy evolution. We present an estimate of the stellar contribution in a sample of low luminosity BL Lac type objects. We have performed stellar population synthesis for a sample of 19 objects selected from Marchã et al. (1996, MNRAS 281, 425). The stellar content is quantified using the equivalent widths of all absorption features available throughout the spectrum. The synthesis is done by a variant of the GPG method (Pelat: 1997, MNRAS 284, 365).