2,350 research outputs found

    Protective factors for teen mothers: relations among social support, psychological resources, and child rearing practices

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    2012 Summer.Includes bibliographical references.Teen mothers face increased challenges when rearing children, largely influenced by development as an adolescent and the support networks they have available to them. Based on two theories of parental and adolescent development, measures of well-being including self-efficacy, depression, and future orientation are mechanisms that can be altered by support networks, and function as protective factors for functional parenting. This study of 344 teen mothers tests the hypotheses that teen mothers who have more supportive primary social networks have greater confidence in parenting abilities, less propensity towards depression, and a more optimistic sense of the future. Results indicate that relations of support functions (intimacy and support satisfaction) and nurturant child rearing practices are partially mediated by self-efficacy and fully mediated by depression. These findings emphasize the importance of supportive characteristics in support networks for teen mothers and parental well-being, both of which may foster the development of non-coercive parenting

    The age of 47Tuc from self-consistent isochrone fits to colour-magnitude diagrams and the eclipsing member V69

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    Our aim is to derive a self-consistent age, distance and composition for the globular cluster 47 47\,Tucanae (47 47\,Tuc; NGC104). First, we reevaluate the reddening towards the cluster resulting in a nominal E(B−V)=0.03±0.01E(B-V)=0.03\pm0.01 as the best estimate. The TeffT_{\rm eff} of the components of the eclipsing binary member V69 is found to be 5900±725900\pm72 K from both photometric and spectroscopic evidence. This yields a true distance modulus (m−M)0=13.21±0.06(m-M)_0=13.21\pm0.06(random)±0.03 \pm0.03 (systematic) to 47 47\,Tuc when combined with existing measurements of V69 radii and luminosity ratio. We then present a new completely self-consistent isochrone fitting method to ground based and HST\textit{HST} cluster colour-magnitude diagrams and the eclipsing binary member V69. The analysis suggests that the composition of V69, and by extension one of the populations of 47 47\,Tuc, is given by [Fe/H]∼−0.70\sim-0.70, [O/Fe]∼+0.60\sim+0.60, and Y∼0.250Y\sim0.250 on the solar abundance scale of Asplund, Grevesse & Sauval. However, this depends on the accuracy of the model TeffT_{\rm eff} scale which is 50-75 K cooler than our best estimate but within measurement uncertainties. Our best estimate of the age of 47 47\,Tuc is 11.8 Gyr, with firm (3σ3 \sigma) lower and upper limits of 10.4 and 13.4 Gyr, respectively, in satisfactory agreement with the age derived from the white dwarf cooling sequence if our determination of the distance modulus is adopted.Comment: 19 pages, 8 figures, accepted for publication in MNRA

    Plant genomics in lentil breeding: development of a cDNA-based rapid screening method for Ascochyta blight resistance in lentil (Lens culinaris L.)

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    Non-Peer ReviewedAscochyta blight causes severe crop losses in temperate lentil production areas around the world, including Saskatchewan. At present there is no reliable system available to breeders for identifying blight resistant lentil lines. We are trying to develop a reliable, high throughput and low cost cDNA based system for screening lentil germplasm for polygenic resistance to Ascochyta blight. We have chosen the Ascochyta blight susceptible lentil variety Richlea and the closely related resistant breeding line 1156-2-17A for this study. Lentil plants were inoculated with spore suspensions of Ascochyta under conditions that clearly showed the difference in disease resistance between these lines. Tissue collected from resistant and susceptible lines at different times after inoculation will be used for extraction of total RNA–representing all the genes expressed by the plants in response to Ascochyta infection. Complementary DNA (cDNA) made from these RNA samples along with mock-inoculated controls will be visualized on poly acrylamide gels using the technique of ‘differential display’. We intend to identify the sequences of lentil genes expressed only by the resistant lines in response to Ascochyta infection and use them for developing molecular markers for the resistance trait. cDNA samples made from these plants will also be useful in developing a cDNA library of lentil tissue for future EST projects

    An extended quantitative model for super-resolution optical fluctuation imaging (SOFI)

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    Super-resolution optical fluctuation imaging (SOFI) provides super-resolution (SR) fluorescence imaging by analyzing fluctuations in the fluorophore emission. The technique has been used both to acquire quantitative SR images and to provide SR biosensing by monitoring changes in fluorophore blinking dynamics. Proper analysis of such data relies on a fully quantitative model of the imaging. However, previous SOFI imaging models made several assumptions that can not be realized in practice. In this work we address these limitations by developing and verifying a fully quantitative model that better approximates real-world imaging conditions. Our model shows that (i) SOFI images are free of bias, or can be made so, if the signal is stationary and fluorophores blink independently, (ii) allows a fully quantitative description of the link between SOFI imaging and probe dynamics, and (iii) paves the way for more advanced SOFI image reconstruction by offering a computationally fast way to calculate SOFI images for arbitrary probe, sample and instrumental properties
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