1,515 research outputs found

    The population of propellers in Saturn's A Ring

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    We present an extensive data set of ~150 localized features from Cassini images of Saturn's Ring A, a third of which are demonstrated to be persistent by their appearance in multiple images, and half of which are resolved well enough to reveal a characteristic "propeller" shape. We interpret these features as the signatures of small moonlets embedded within the ring, with diameters between 40 and 500 meters. The lack of significant brightening at high phase angle indicates that they are likely composed primarily of macroscopic particles, rather than dust. With the exception of two features found exterior to the Encke Gap, these objects are concentrated entirely within three narrow (~1000 km) bands in the mid-A Ring that happen to be free from local disturbances from strong density waves. However, other nearby regions are similarly free of major disturbances but contain no propellers. It is unclear whether these bands are due to specific events in which a parent body or bodies broke up into the current moonlets, or whether a larger initial moonlet population has been sculpted into bands by other ring processes.Comment: 31 pages, 10 figures; Accepted at A

    The significance of liturgical acts: Using Victoria Welby's semiotics as a method for liturgical theology

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    Thesis advisor: John BaldovinThesis advisor: Liam BerginThesis (STL) — Boston College, 2020.Submitted to: Boston College. School of Theology and Ministry.Discipline: Sacred Theology

    Somatic-Vegetative Symptoms of Depression Predict 6-Year Increases in Insulin Resistance: Data from the Pittsburgh Healthy Heart Project

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    poster abstractAlthough prospective studies suggest a bidirectional association between depression and type 2 diabetes, few studies have examined depressive symptom clusters or concurrently evaluated both directions of this relationship. Consequently, our objective was to examine the longitudinal, bidirectional associations between the somatic-vegetative and cognitive-affective clusters of depressive symptoms and insulin resistance, which is implicated in the pathophysiology of type 2 diabetes. Participants were 269 adults (baseline age range: 50-70 years, 55% female, 14% non-white) without diabetes enrolled in the Pittsburgh Healthy Heart Project, a prospective cohort study. At baseline and the 6-year visits, participants completed the Beck Depression Inventory-II (BDI-II) to assess depressive symptoms and underwent a blood draw to quantify fasting serum insulin and glucose. We examined baseline BDI-II total and subscale scores as predictors of 6-year change in the homeostatic model assessment (HOMA) score, an index of insulin resistance computed from fasting insulin and glucose. We also examined baseline HOMA score as a predictor of 6-year change in BDI-II total and subscale scores. HOMA and BDI-II change were computed as follow-up score minus baseline score. Regression analyses, adjusted for baseline HOMA score and demographic factors, revealed that the baseline BDI-II somatic-vegetative score (beta=.14, p=.03), but not the total (beta=.10, p=.11) or cognitive-affective (beta=.004, p=.95) scores, was a predictor of 6-year increases in the HOMA score. The pattern of results was similar after further adjustment for body mass index, except that the BDI-II total score became a predictor of HOMA change (beta=.13, p=.03). In contrast, the baseline HOMA score did not predict 6-year change in BDI-II total, somatic-vegetative, or cognitive-affective scores (all p’s>.48). Our findings indicate that older adults experiencing the somatic-vegetative symptoms of depression (e.g., fatigue, sleep disturbance, and appetite changes) may be at an increased risk of insulin resistance and subsequent type 2 diabetes

    Depressive symptom clusters as predictors of 6-year increases in insulin resistance: data from the Pittsburgh Healthy Heart Project

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    OBJECTIVE: To examine longitudinal bidirectional associations between two depressive symptom clusters-the cognitive-affective and somatic-vegetative clusters--and insulin resistance, a marker of prediabetes. METHODS: Participants were 269 adults aged 50 to 70 years without diabetes enrolled in the Pittsburgh Healthy Heart Project, a prospective cohort study. At baseline and 6-year visits, participants completed the Beck Depression Inventory-II (BDI-II) and underwent a blood draw to quantify fasting insulin and glucose. We examined baseline BDI-II total, cognitive-affective, and somatic-vegetative scores as predictors of 6-year change in the homeostatic model of assessment (HOMA) score, an estimate of insulin resistance computed from fasting insulin and glucose. We also examined baseline HOMA score as a predictor of 6-year change in BDI-II total and subscale scores. RESULTS: Regression analyses, adjusted for demographic factors and baseline HOMA score, revealed that the baseline BDI-II somatic-vegetative score (β = 0.14, p = .025), but not the cognitive-affective (β = 0.001, p = .98) or total (β = 0.10, p = .11) scores, predicted 6-year HOMA change. This result persisted in models controlling for anxiety symptoms and hostility. Several factors were examined as candidate mediators; however, only change in body mass index was a significant mediator (p = .042), accounting for 23% of the observed association. Baseline HOMA score did not predict 6-year change in BDI-II total or subscale scores (all p values >.56). CONCLUSIONS: Among adults aged 50 to 70 years, the somatic-vegetative symptoms of depression (e.g., fatigue, sleep disturbance, and appetite changes) may worsen insulin resistance and increase diabetes risk, partly, by increasing body mass index

    Improving the Voter Experience: Reducing Polling Place Wait Times by Measuring Lines and Managing Polling Place Resources

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    Long lines at the polls can undermine the voting experience, even to the point of discouraging people from voting. Reducing polling place wait times by measuring lines and managing polling place resources can improve the voting experience

    Insomnia as an Independent Predictor of Incident Cardiovascular Disease in HIV: Data from the Veterans Aging Cohort Study

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    Background: Insomnia is associated with increased cardiovascular disease (CVD) risk in the general population and is highly prevalent in people with HIV. The CVD risk conferred by insomnia in the HIV population is unknown. Methods: Using the Veterans Aging Cohort Study-Survey Cohort, insomnia symptoms were measured and dummy coded with the item, “Difficulty falling or staying asleep?” (5-point scale from no difficulty to bothers a lot). Incident CVD event ICD-9 codes (acute myocardial infarction, stroke, or coronary artery revascularization) were identified with VA and Medicare administrative data and VA fee-for-service data. Those with baseline CVD were excluded. Results: HIV-infected (N=3,108) veterans had a median follow-up time of 10.8 years, during which 267 CVD events occurred. Compared to HIV-infected veterans with no difficulty falling or staying asleep, HIV-infected veterans bothered a lot by insomnia symptoms had an increased risk of incident CVD after adjusting for demographics (HR=1.64, 95%CI=1.16-2.31, p=.005), CVD risk factors (HR=1.62, 95%CI=1.14-2.30, p=.007), additional potential confounders (hepatitis C infection, renal disease, anemia, alcohol use, cocaine use; HR=1.70, 95%CI=1.19-2.43, p=.003), and HIV-specific factors (HIV-1 RNA, CD4+ T-cell count, ART; HR=1.66, 95%CI=1.16-2.37, p=.005). Additional adjustment for non-benzodiazepine sleep medication (HR=1.62, 95%CI=1.13-2.32, p=.009) did not attenuate the association; however, it fell short of significance at p < .01 after adjustment for depressive symptoms (HR=1.51, 95%CI=0.98-2.32, p=.060) or antidepressant medication (HR=1.51, 95%CI=1.04-2.19, p=.031). Conclusion: Highly bothersome insomnia symptoms were significantly associated with incident CVD in HIV-infected veterans, suggesting that insomnia may be a novel, modifiable risk factor for CVD in HIV

    Use of IU parallel computing resources and high performance file systems - July 2013 to Dec 2014

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    This report details use of IU's parallel computing resources and high performance file systems from July 2013 through December 2014

    Drp2 and Periaxin Form Cajal Bands with Dystroglycan But Have Distinct Roles in Schwann Cell Growth

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    Cajal bands are cytoplasmic channels flanked by appositions where the abaxonal surface of Schwann cell myelin apposes and adheres to the overlying plasma membrane. These appositions contain a dystroglycan complex that includes periaxin and dystrophin-related protein 2 (Drp2). Loss of periaxin disrupts appositions and Cajal bands in Schwann cells and causes a severe demyelinating neuropathy in mouse and man. Here we have investigated the role of mouse Drp2 in apposition assembly and Cajal band function and compared it to periaxin. We show that Periaxin and Drp2 are not only both required to form appositions, but they must also interact. Periaxin-Drp2 interaction is also required for Drp2 phosphorylation but phosphorylation is not required for the assembly of appositions. Drp2 loss causes corresponding increases in Dystrophin family members, utrophin and dystrophin Dp116 though dystroglycan remains unchanged. We also show that all dystroglycan complexes in Schwann cells utilise the uncleaved form of β-dystroglycan. Drp2-null Schwann cells have disrupted appositions and Cajal bands, and they undergoe focal hypermyelination and concomitant demyelination. Nevertheless, they do not have the short internodal lengths and associated reduced nerve conduction velocity seen in the absence of periaxin, showing that periaxin regulates Schwann cell elongation independent of its role in the dystroglycan complex. We conclude that the primary role of the dystroglycan complex in appositions is to stabilize and limit the radial growth of myelin

    Revision of the \u3cem\u3eMesobuthus caucasicus\u3c/em\u3e complex from Central Asia, with descriptions of six new species (Scorpiones: Buthidae)

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    A widespread Mesobuthus caucasicus complex, which includes some of the most common scorpions found from the Caucasus to China, is revised for the first time based on new extensive collections from Central Asia, using both morphological and DNA marker data. Mesobuthus caucasicus (Nordmann, 1840), s.str. is restricted to the Caucasus Mts. Four taxa are elevated to species rank: M. fuscus (Birula, 1897) (Tajikistan), M. intermedius (Birula, 1897) (Tajikistan), M. kaznakovi (Birula, 1904) (Tajikistan, Uzbekistan), and M. parthorum (Pocock, 1889) (Afghanistan, Iran, Turkmenistan). Six new species are described: M. brutus sp. n. (Iran), M. elenae sp. n. (Tajikistan, Uzbekistan), M. gorelovi sp. n. (Kazakhstan, Turkmenistan, Uzbekistan), M. kreuzbergi sp. n. (Tajikistan, Uzbekistan), M. mischi sp. n. (Afghanistan), and M. nenilini sp. n. (Uzbekistan). The most common species in Central Asia is a psammophilic Mesobuthus gorelovi sp. n., widespread through lowland sand deserts across Turkmenistan (Karakum), Uzbekistan (Kizylkum), and Kazakhstan (north to Baigakum and Moyinkum). A key to all studied species is provided. A DNA phylogeny based on COI and 16S rRNA markers is presented including nine Central Asian species (M. elenae sp. n., M. fuscus, M. gorelovi sp. n., M. intermedius, M. kaznakovi, M. kreuzbergi sp. n., M. mischi sp. n., M. nenilini sp. n., and M. parthorum) and M. caucasicus from Turkey. A deep phylogenetic diversity across Central Asia is revealed. Historical biogeographic scenarios for this scorpion group are discussed, including fragmentation in mountain valleys and expansion across sand deserts in Central Asia. The monotypic scorpion genus Afghanobuthus Lourenço, 2005 and its single species A. naumanni Lourenço, 2005, from Afghanistan, are demonstrated to be junior synonyms, respectively, of Mesobuthus Vachon, 1950, and M. parthorum (Pocock, 1889) from the same area

    What is Cyberinfrastructure?

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    Cyberinfrastructure is a word commonly used but lacking a single, precise definition. One recognizes intuitively the analogy with infrastructure, and the use of cyber to refer to thinking or computing – but what exactly is cyberinfrastructure as opposed to information technology infrastructure? Indiana University has developed one of the more widely cited definitions of cyberinfrastructure: "Cyberinfrastructure consists of computing systems, data storage systems, advanced instruments and data repositories, visualization environments, and people, all linked together by software and high performance networks to improve research productivity and enable breakthroughs not otherwise possible." A second definition, more inclusive of scholarship generally and educational activities, has also been published and is useful in describing cyberinfrastructure: "Cyberinfrastructure consists of systems, data and information management, advanced instruments, visualization environments, and people, all linked together by software and advanced networks to improve scholarly productivity and enable knowledge breakthroughs and discoveries not otherwise possible." In this paper, we describe the origin of the term cyberinfrastructure based on the history of the root word infrastructure, discuss several terms related to cyberinfrastructure, and provide several examples of cyberinfrastructure
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