1,818 research outputs found

    Probing the Fitting Accuracy of Active Galaxy Spectra

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    Prior to this study, Dr. Vardha N. Bennert and collaborators selected a sample of ~100 local active galaxies to study the relationships between black hole mass and host galaxy properties. The broad Hβ width is necessary to determine black hole mass. This value is determined using a spectral decomposition code was scripted in IDL by Dr. Daeseong Park. The script fit spectral features and collected data for properties such as width of emission lines and continuum contribution percentages. The results were logged for further analysis. To probe the accuracy of the fitting process, artificial spectra were created and fitted to determine if the output width values for Hβ reasonably match the width values of the input components contained in the pseudo spectra. To test fitting accuracy with spectra containing variable host galaxy continuum contributions, the artificial spectra were given such contributions. For this study, the extracted components from the real active galaxy spectra were used to create artificial spectra containing relevant characteristics typically found in the sample objects\u27 spectra. 105 artificial spectra were created with their components cataloged. The pseudo-spectra contained features whose physical quantities spanned ranges typically found within the sample of real, collected spectra, as well as added random noise, in order to appropriately represent the original sample set. The varied components were Hβ width and continuum contributions from a power law continuum, host galaxy starlight, and FeII emissions. The artificial spectra were then ran through the same IDL decomposition code that originally fit the real objects. The quantitative results of the applied fitting process were then compared with the properties of the known components that composed the artificial spectra. The comparison of input versus output through the IDL code produces a fitting percent error that was used for analysis of accuracy of fit features. The Hβ emission line width is the focus feature for contrast between the variable pseudo spectra. The errors were plotted against the variable components in order to determine a correlation between feature properties and fitting error, if any exist. The results of my research suggest that the IDL fitting code recovers the input parameters to a typical uncertainty of ~(5±5)% Moreover, it is independent of Hβ full width at half maximum, power law continuum contribution percentage, host galaxy continuum contribution percentage, or FeII continuum contribution percentage. The creation of more artificial spectra is necessary to create a better representation of active galaxy spectra that may include extreme features not included in this study

    Three-point correlations for quantum star graphs

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    We compute the three point correlation function for the eigenvalues of the Laplacian on quantum star graphs in the limit where the number of edges tends to infinity. This extends a work by Berkolaiko and Keating, where they get the 2-point correlation function and show that it follows neither Poisson, nor random matrix statistics. It makes use of the trace formula and combinatorial analysis.Comment: 10 pages, 2 figure

    Behavioral and other phenotypes in a cytoplasmic Dynein light intermediate chain 1 mutant mouse

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    The cytoplasmic dynein complex is fundamentally important to all eukaryotic cells for transporting a variety of essential cargoes along microtubules within the cell. This complex also plays more specialized roles in neurons. The complex consists of 11 types of protein that interact with each other and with external adaptors, regulators and cargoes. Despite the importance of the cytoplasmic dynein complex, we know comparatively little of the roles of each component protein, and in mammals few mutants exist that allow us to explore the effects of defects in dynein-controlled processes in the context of the whole organism. Here we have taken a genotype-driven approach in mouse (Mus musculus) to analyze the role of one subunit, the dynein light intermediate chain 1 (Dync1li1). We find that, surprisingly, an N235Y point mutation in this protein results in altered neuronal development, as shown from in vivo studies in the developing cortex, and analyses of electrophysiological function. Moreover, mutant mice display increased anxiety, thus linking dynein functions to a behavioral phenotype in mammals for the first time. These results demonstrate the important role that dynein-controlled processes play in the correct development and function of the mammalian nervous system

    A Comparison of Maternal versus Paternal Nonverbal Behavior During Child Pain

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    Parental behavior plays a significant role in children's pain response. Prior research has found generally no differences between mothers’ and fathers’ verbal behavior during child pain. This study compared mothers’ and fathers’ nonverbal behavior during child pain. Nonverbal behavior of mothers (n= 39) and fathers (n= 39) of 39 children (20 boys) aged 8 to 12 years who participated in the cold pressor task (counterbalanced once with each parent) was coded. A range of nonverbal behaviors were coded, including distraction, physical proximity, physical comfort/reassurance, procedure-related attending behavior, and fidgeting. The most common behaviors parents engaged in were fidgeting, procedure-related attending behaviors, and physical proximity. Results indicated that the types of nonverbal behavior parents engage in did not differ between mothers and fathers. However, children of mothers who engaged in more physical comfort/reassurance reported higher levels of pain intensity, and children of mothers who engaged in more procedure-related attending behaviors had lower pain tolerance. Further, both mothers and fathers who engaged in higher levels of verbal nonattending behaviors also engaged in lower levels of nonverbal procedure-related attending behaviors. These findings further support the importance of considering the influence of mothers and fathers in children's pain, and provide novel insights into the role of nonverbal behavior

    Catastrophic thinking about pain: A critical appraisal highlighting the importance of the social context and balance

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    Numerous research studies have shown that endorsing a catastrophic interpretation about pain is associated with deleterious outcomes, such as higher levels of distress, pain intensity and disability for the person in pain. The fear-avoidance model has been found to be useful in explaining these associations by stressing that heightened feelings of distress and behaviour aimed at reducing or avoiding pain might be adaptive in an acute pain context but can become maladaptive when the pain becomes chronic. Pain is rarely a private event and the communal coping model underscores that the heightened pain expression in people endorsing catastrophic thoughts about pain could have a social, communicative function of eliciting empathic responses in others. However, these models are not all-encompassing. In particular, neither of the models takes into account the growing evidence indicating that catastrophic thinking in observers can also impact their emotional experience and behaviour in response to the other’s pain. Moreover, the context of multiple goals in which pain and pain behaviour occurs is largely ignored in both models. In this article we present an integrative perspective on catastrophic thinking that takes into account the social system and interplay between different goals people in pain and observers might pursue (e.g., school/work performance, leisure, social engagement). Specifically, this integrative perspective stresses the importance of considering the bidirectional influence between catastrophic thoughts in the person experiencing pain and observers. Furthermore, the importance of balance between pain-relief and other important goals as well as in the level of catastrophic thoughts in understanding the maladaptive influence of catastrophic thinking will be underlined. Clinical implications and future research directions of this integrated perspective are discussed
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