3,133 research outputs found

    A practical model of convective dynamics for stellar evolution calculations

    Full text link
    Turbulent motions in the interior of a star play an important role in its evolution, since they transport chemical species, thermal energy and angular momentum. Our overall goal is to construct a practical turbulent closure model for convective transport that can be used in a multi-dimensional stellar evolution calculation including the effects of rotation, shear and magnetic fields. Here, we focus on the first step of this task: capturing the well-known transition from radiative heat transport to turbulent convection with and without rotation, as well as the asymptotic relationship between turbulent and radiative transport in the limit of large Rayleigh number. We extend the closure model developed by Ogilvie (2003) and Garaud and Ogilvie (2005) to include heat transport and compare it with experimental results of Rayleigh-Benard convection.Comment: Conference proceeding for poster at conference "Unsolved problems in Stellar Physics

    Inspecting and Buying a New or Used Saddle

    Get PDF
    Whether purchasing a new or used saddle, several aspects should be evaluated. To determine if the saddle is sturdy and well-made some aspects to check include the leather, stitching, metal fittings and tree

    An Examination of Diversity, Equity, Inclusion, and Belonging (DEIB) Initiatives in Large U.S. Public Accounting Firms to Recruit and Retain Women and Minorities in the Workplace

    Get PDF
    Public accounting firms are currently facing lower recruitment and retention rates, but the use of effective and authentic diversity, equity, inclusion, and belonging initiatives can better the workplace environment. Through different DEIB initiatives, like mentorship programs, anti-bias training, employee resource groups, inclusive leadership, and pay equity, women and minorities can feel represented and comfortable in the workplace. From analyzing Big Four DEI Transparency Reports, a relationship is shown between effective DEIB initiatives and recruitment and retention within the firms. Furthermore, these DEIB initiatives are important aspects of a firm’s business strategy to be able to compete with one another

    Differential Functional Connectivity of Rostral Anterior Cingulate Cortex During Emotional Interference

    Get PDF
    The rostral-ventral subdivision of the anterior cingulate cortex (rACC) plays a key role in the regulation of emotional processing. Although rACC has strong anatomical connections with anterior insular cortex (AIC), amygdala, prefrontal cortex and striatal brain regions, it is unclear whether the functional connectivity of rACC with these regions changes when regulating emotional processing. Furthermore, it is not known whether this connectivity changes with deficits in emotion regulation seen in different kinds of anxiety and depression. To address these questions regarding rACC functional connectivity, non-patients high in self-reported anxious apprehension (AP), anxious arousal (AR), anhedonic depression (AD) or none (CON) indicated the ink color of pleasant, neutral and unpleasant words during functional magnetic resonance imaging. While ignoring task-irrelevant unpleasant words, AD and CON showed an increase in the functional connectivity of rACC with AIC, putamen, caudate and ventral pallidum. There was a decrease in this connectivity in AP and AR, with AP showing greater reduction than AR. These findings provide support for the role of rACC in integrating interoceptive, emotional and cognitive functions via interactions with insula and striatal regions during effective emotion regulation in healthy individuals and a failure of this integration that may be specific to anxiety, particularly AP

    Neural Correlates of Suspiciousness and Interactions with Anxiety During Emotional and Neutral Word Processing

    Get PDF
    Suspiciousness is usually classified as a symptom of psychosis, but it also occurs in depression and anxiety disorders. Though how suspiciousness overlaps with depression is not obvious, suspiciousness does seem to overlap with anxious apprehension and anxious arousal (e.g., verbal iterative processes and vigilance about environmental threat). However, suspiciousness also has unique characteristics (e.g., concern about harm from others and vigilance about social threat). Given that both anxiety and suspiciousness have been associated with abnormalities in emotion processing, it is unclear whether it is the unique characteristics of suspiciousness or the overlap with anxiety that drive abnormalities in emotion processing. Event-related brain potentials were obtained during an emotion-word Stroop task. Results indicated that suspiciousness interacts with anxious apprehension to modulate initial stimulus perception processes. Suspiciousness is associated with attention to all stimuli regardless of emotion content. In contrast, anxious arousal is associated with a later response to emotion stimuli only. These results suggest that suspiciousness and anxious apprehension share overlapping processes, but suspiciousness alone is associated with a hyperactive early vigilance response. Depression did not interact with suspiciousness to predict response to emotion stimuli. These findings suggest that it may be informative to assess suspiciousness in conjunction with anxiety in order to better understand how these symptoms interact and contribute to dysfunctional emotion processing

    Dominating the Antarctic environment: bryophytes in a time of change

    Get PDF
    Polar ecosystems, and particularly Antarctica, are one of the few environs in which bryophytes dominate the flora. Their success in these regions is due to bryophytes’ ability to withstand an array of harsh conditions through their poikilohydric lifestyle. However, the unique conditions that allow bryophytes to proliferate over other forms of vegetation also create considerable limitations to growth and photosynthetic activity. High latitude areas are already experiencing some of the most pronounced and rapid climatic change, especially in the Arctic, the Sub-Antarctic Islands and Maritime Antarctica, and these are predicted to continue over the next century. This climatic change is already impacting the flora of the polar regions both via direct and/or indirect impacts on plant species. Water availability and temperature are undoubtedly the most influential factors that determine bryophyte productivity in the Antarctic, but the ozone hole is also having an impact either directly via increased ultraviolet-B radiation and/or indirectly through the increasing wind speeds associated with ozone depletion. In a time of shifting climate the dominance of bryophytes in these regions may be threatened

    An Sp185/333 gene cluster from the purple sea urchin and putative microsatellite-mediated gene diversification

    Get PDF
    Abstract Background The immune system of the purple sea urchin, Strongylocentrotus purpuratus, is complex and sophisticated. An important component of sea urchin immunity is the Sp185/333 gene family, which is significantly upregulated in immunologically challenged animals. The Sp185/333 genes are less than 2 kb with two exons and are members of a large diverse family composed of greater than 40 genes. The S. purpuratus genome assembly, however, contains only six Sp185/333 genes. This underrepresentation could be due to the difficulties that large gene families present in shotgun assembly, where multiple similar genes can be collapsed into a single consensus gene. Results To understand the genomic organization of the Sp185/333 gene family, a BAC insert containing Sp185/333 genes was assembled, with careful attention to avoiding artifacts resulting from collapse or artificial duplication/expansion of very similar genes. Twelve candidate BAC assemblies were generated with varying parameters and the optimal assembly was identified by PCR, restriction digests, and subclone sequencing. The validated assembly contained six Sp185/333 genes that were clustered in a 34 kb region at one end of the BAC with five of the six genes tightly clustered within 20 kb. The Sp185/333 genes in this cluster were no more similar to each other than to previously sequenced Sp185/333 genes isolated from three different animals. This was unexpected given their proximity and putative effects of gene homogenization in closely linked, similar genes. All six genes displayed significant similarity including both 5' and 3' flanking regions, which were bounded by microsatellites. Three of the Sp185/333 genes and their flanking regions were tandemly duplicated such that each repeated segment consisted of a gene plus 0.7 kb 5' and 2.4 kb 3' of the gene (4.5 kb total). Both edges of the segmental duplications were bounded by different microsatellites. Conclusions The high sequence similarity of the Sp185/333 genes and flanking regions, suggests that the microsatellites may promote genomic instability and are involved with gene duplication and/or gene conversion and the extraordinary sequence diversity of this family
    corecore