On the Impact of Inclination-Dependent Attenuation on the Derived Star Formation Histories of Disk Galaxies

The physical properties of a galaxy (e.g., its star-formation history and dust content) regulate the distribution of light that is emitted by stars and attenuated by the interstellar gas and dust. This attenuation by dust can have a significant impact on the observed spectral energy distribution (SED) of a disk galaxy, especially when taking into account its viewing angle (i.e., inclination). For example, as the inclination angle of a galactic disk changes from face-on to edge-on (i.e., i = 0 deg to i = 90 deg), the proportion of light that is attenuated along the line of sight increases, due to an increasing column density of dust. Therefore, additional care must be taken when modeling the SED of a disk galaxy to account for any inclination dependence. In this work, we develop and implement an inclination-dependent attenuation prescription into our SED fitting code, Lightning, to more accurately derive the physical properties of disk galaxies. First, we present the details of our SED fitting code, Lightning, as it is the cornerstone of our inclination-dependent analyses. We discuss all of the models in Lightning, which can include contributions from a variety of sources, along with the available algorithms to fit the models to observations. Then, to show the future potential of Lightning, we present several examples using a variety of observational data. Next, to better understand how inclination affects the physical properties of disk galaxies, we apply our prescription on two respective galactic samples to (1) study the impact of inclination-dependent attenuation on derived stellar properties and (2) examine and quantify how commonly used star formation rate (SFR) estimators depend on inclination. For the first application, we compare our inclination-dependent attenuation prescription with a more traditional inclination-independent attenuation prescription. Our results indicate stark statistical differences in the derived optical attenuation and stellar masses, with the traditional attenuation prescription resulting in these properties being underestimated compared to the inclination-dependent attenuation prescription at high inclinations. Therefore, the results from this application suggest that SED fitting assuming inclination-independent attenuation potentially underestimates these properties in highly inclined disk galaxies. For the second application, We find that two commonly used SFR estimators (the hybrid UV+IR and AFUV-beta relations) present clear dependencies on inclination. To quantify these dependencies, we expand the parametric form of the estimators to include an inclination-dependence. We then compare both of these new inclination-dependent estimators to similar inclination-independent relations found in the literature. From this comparison, we find that our inclination-dependent relations result in a reduction in the residual scatter of the derived SFRs of our sample by approximately a factor of two. Therefore, this second application demonstrates that inclination must be considered in SFR estimators to produce more accurate SFR estimates in disk galaxies. Overall, this work provides the crucial steps towards understanding and incorporating the impact of inclination-dependence on the derived star-formation histories of disk galaxies. It additionally presents a novel tool (Lightning) which can be used in future studies to more accurately account for this inclination-dependence

On the Impact of Inclination-Dependent Attenuation on the Derived Star Formation Histories of Disk Galaxies

The physical properties of a galaxy (e.g., its star-formation history and dust content) regulate the distribution of light that is emitted by stars and attenuated by the interstellar gas and dust. This attenuation by dust can have a significant impact on the observed spectral energy distribution (SED) of a disk galaxy, especially when taking into account its viewing angle (i.e., inclination). For example, as the inclination angle of a galactic disk changes from face-on to edge-on (i.e., i = 0 deg to i = 90 deg), the proportion of light that is attenuated along the line of sight increases, due to an increasing column density of dust. Therefore, additional care must be taken when modeling the SED of a disk galaxy to account for any inclination dependence. In this work, we develop and implement an inclination-dependent attenuation prescription into our SED fitting code, Lightning, to more accurately derive the physical properties of disk galaxies. First, we present the details of our SED fitting code, Lightning, as it is the cornerstone of our inclination-dependent analyses. We discuss all of the models in Lightning, which can include contributions from a variety of sources, along with the available algorithms to fit the models to observations. Then, to show the future potential of Lightning, we present several examples using a variety of observational data. Next, to better understand how inclination affects the physical properties of disk galaxies, we apply our prescription on two respective galactic samples to (1) study the impact of inclination-dependent attenuation on derived stellar properties and (2) examine and quantify how commonly used star formation rate (SFR) estimators depend on inclination. For the first application, we compare our inclination-dependent attenuation prescription with a more traditional inclination-independent attenuation prescription. Our results indicate stark statistical differences in the derived optical attenuation and stellar masses, with the traditional attenuation prescription resulting in these properties being underestimated compared to the inclination-dependent attenuation prescription at high inclinations. Therefore, the results from this application suggest that SED fitting assuming inclination-independent attenuation potentially underestimates these properties in highly inclined disk galaxies. For the second application, We find that two commonly used SFR estimators (the hybrid UV+IR and AFUV-beta relations) present clear dependencies on inclination. To quantify these dependencies, we expand the parametric form of the estimators to include an inclination-dependence. We then compare both of these new inclination-dependent estimators to similar inclination-independent relations found in the literature. From this comparison, we find that our inclination-dependent relations result in a reduction in the residual scatter of the derived SFRs of our sample by approximately a factor of two. Therefore, this second application demonstrates that inclination must be considered in SFR estimators to produce more accurate SFR estimates in disk galaxies. Overall, this work provides the crucial steps towards understanding and incorporating the impact of inclination-dependence on the derived star-formation histories of disk galaxies. It additionally presents a novel tool (Lightning) which can be used in future studies to more accurately account for this inclination-dependence

Spatial Relations and Natural-Language Semantics for Indoor Scenes

Over the past 15 years, there have been increased efforts to represent and communicate spatial information about entities within indoor environments. Automated annotation of information about indoor environments is needed for natural-language processing tasks, such as spatially anchoring events, tracking objects in motion, scene descriptions, and interpretation of thematic places in relationship to confirmed locations. Descriptions of indoor scenes often require a fine granularity of spatial information about the meaning of natural-language spatial utterances to improve human-computer interactions and applications for the retrieval of spatial information. The development needs of these systems provide a rationale as to why—despite an extensive body of research in spatial cognition and spatial linguistics—it is still necessary to investigate basic understandings of how humans conceptualize and communicate about objects and structures in indoor space. This thesis investigates the alignment of conceptual spatial relations and naturallanguage (NL) semantics in the representation of indoor space. The foundation of this work is grounded in spatial information theory as well as spatial cognition and spatial linguistics. In order to better understand how to align computational models and NL expressions about indoor space, this dissertation used an existing dataset of indoor scene descriptions to investigate patterns in entity identification, spatial relations, and spatial preposition use within vista-scale indoor settings. Three human-subject experiments were designed and conducted within virtual indoor environments. These experiments investigate alignment of human-subject NL expressions for a sub-set of conceptual spatial relations (contact, disjoint, and partof) within a controlled virtual environment. Each scene was designed to focus participant attention on a single relation depicted in the scene and elicit a spatial preposition term(s) to describe the focal relationship. The major results of this study are the identification of object and structure categories, spatial relationships, and patterns of spatial preposition use in the indoor scene descriptions that were consistent across both open response, closed response and ranking type items. There appeared to be a strong preference for describing scene objects in relation to the structural objects that bound the room depicted in the indoor scenes. Furthermore, for each of the three relations (contact, disjoint, and partof), a small set of spatial prepositions emerged that were strongly preferred by participants at statistically significant levels based on the overall frequency of response, image sorting, and ranking judgments. The use of certain spatial prepositions to describe relations between room structures suggests there may be differences in how indoor vista-scale space is understood in relation to tabletop and geographic scales. Finally, an indoor scene description corpus was developed as a product of this work, which should provide researchers with new human-subject based datasets for training NL algorithms used to generate more accurate and intuitive NL descriptions of indoor scenes

Dreams Just Dreams

https://digitalcommons.library.umaine.edu/mmb-vp/3088/thumbnail.jp

Serpents and Salvation: Female Snake Transformation in Sayohime and Chūjōhime Gohonji

This thesis examines the use of the female snake transformation trope, particularly in two sekkyō works, Sayohime and Chūjōhime gohonji. The woman who transforms into a giant serpent due to delusive attachment is an iconic figure with a long history in Japanese literature, and while it has often served as an expression of the inherent sinfulness of women, it has also been used to create a powerful message of salvation for women Sayohime and Chūjōhime gohonji are excellent examples of such a use, and by examining the ways the snake-woman trope affects the narrative in each of these works, we gain insight into how such a seemingly misogynistic trope can also have positive significance for women in Buddhism. The introductory chapter lays the groundwork necessary for an analysis of the trope, researching possible origins of the snake-woman from Buddhist and nativeJapanese influences and tracing the development of this trope through the medieval period by focusing on the most famous of snake-woman tales, the Dōjōji legend. Chapters two and three examine the trope as it is used in Sayohime and Chūjōhime gohonji, exploring the foundational elements informing each work and examining the way the presence of female snake-transformation enriches the message of female salvation that is at the heart of both stories

Improving image analysis in 2DGE-based redox proteomics by labeling protein carbonyl with fluorescent hydroxylamine

Recent advances in redox proteomics have provided significant insight into the role of oxidative modifications in cellular signalling and metabolism. At present, these techniques rely heavily on Western blots to visualize the oxidative modification and corresponding two dimensional (2D) gels for detection of total protein levels, resulting in the duplication of efforts. A major limitation associated with this methodology includes problematic matching up of gels and blots due to the differences in processing and/or image acquisition. In this study, we present a new method which allows detection of protein oxidation and total protein on the same gel to improve matching in image analysis. Furthermore, the digested protein spots are compatible with standard MALDI mass spectrometry protein identification. The methodology highlighted here may be useful in facilitating the development of biomarkers, assessing potential therapeutic targets and elucidating new mechanisms of redox signalling in redox-related conditions

Reframing Engagement Methods for Climate Change Adaptation

Climate change poses known and unknown risks for coastal communities and also challenges for university faculty and local government staff who communicate about climate sciences. Conceived as a way to move beyond traditional models of science communication, this project involved public and private decision makers in specific at-risk communities in Oregon (U.S. Pacific coast) and Maine (Atlantic coast). Both state projects sought to move behavior toward decisive action that results in coastal communities that are more resilient to climate variability at all scales. To promote engagement between project staffs and publics, a dialogic model of communication was advanced, beginning with interviews and focus groups which in turn shaped further engagement through workshops and targeted video products. This means of communication led to a deeper understanding of participants’ knowledge, beliefs, perceptions, values, and barriers to action related to climate change and its effects. Coinciding with this, project participant evaluations in both Oregon and Maine indicate that the workshops and videos were successful at informing them on this complex issue; and in both states, project participation led to action outcomes. We believe that applied elsewhere our multi-faceted and adaptive approach will garner similar results, provided sufficient dedicated staffing and attention to methods