1,389 research outputs found

    Parametric Study of Decay of Homogeneous Isotropic Turbulence Using Large Eddy Simulation

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    Numerical simulations of decaying homogeneous isotropic turbulence are performed with both low-order and high-order spatial discretization schemes. The turbulent Mach and Reynolds numbers for the simulations are 0.2 and 250, respectively. For the low-order schemes we use either second-order central or third-order upwind biased differencing. For higher order approximations we apply weighted essentially non-oscillatory (WENO) schemes, both with linear and nonlinear weights. There are two objectives in this preliminary effort to investigate possible schemes for large eddy simulation (LES). One is to explore the capability of a widely used low-order computational fluid dynamics (CFD) code to perform LES computations. The other is to determine the effect of higher order accuracy (fifth, seventh, and ninth order) achieved with high-order upwind biased WENO-based schemes. Turbulence statistics, such as kinetic energy, dissipation, and skewness, along with the energy spectra from simulations of the decaying turbulence problem are used to assess and compare the various numerical schemes. In addition, results from the best performing schemes are compared with those from a spectral scheme. The effects of grid density, ranging from 32 cubed to 192 cubed, on the computations are also examined. The fifth-order WENO-based scheme is found to be too dissipative, especially on the coarser grids. However, with the seventh-order and ninth-order WENO-based schemes we observe a significant improvement in accuracy relative to the lower order LES schemes, as revealed by the computed peak in the energy dissipation and by the energy spectrum

    Nesting Ecology of Greater Sage-Grouse Centrocercus urophasianus at the Eastern Edge of their Historic Distribution

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    Greater sage-grouse Centrocercus urophasianus populations in North Dakota declined approximately 67% between 1965 and 2003, and the species is listed as a Priority Level 1 Species of Special Concern by the North Dakota Game and Fish Department. The habitat and ecology of the species at the eastern edge of its historical range is largely unknown. We investigated nest site selection by greater sage-grouse and nest survival in North Dakota during 2005 - 2006. Sage-grouse selected nest sites in sagebrush Artemisia spp. with more total vegetative cover, greater sagebrush density, and greater 1-m visual obstruction from the nest than at random sites. Height of grass and shrub (sagebrush) at nest sites were shorter than at random sites, because areas where sagebrush was common were sites in low seral condition or dense clay or clay-pan soils with low productivity. Constant survival estimates of incubated nests were 33% in 2005 and 30% in 2006. Variables that described the resource selection function for nests were not those that modeled nest survival. Nest survival was positively influenced by percentage of shrub (sagebrush) cover and grass height. Daily nest survival decreased substantially when percentage of shrub cover declined below about 9% and when grass heights were less than about 16 cm. Daily nest survival rates decreased with increased daily precipitation

    WEST NILE VIRUS AND FERRUGINOUS HAWKS (BUTEO REGALIS) IN THE NORTHERN GREAT PLAINS

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    Emerging infectious diseases (EID) present significant threats to the conservation of global biodiversity (Daszak et al. 2000). Evaluating impacts (spatial, temporal and demographic) of EIDs on sensitive and declining wildlife populations is challenging because quantitative information is usually dependent on estimates rather than counts (Wobeser 2007) and mortality rates are seldom quantified with conventional monitoring (Naugle et al. 2005). West Nile virus (WNv), a mosquito-borne Flavivirus (family Flaviviridae; Komar 2001), was discovered in northwest Uganda in 1937 (Smithburn et al. 1940). First encountered in the western hemisphere in New York in 1999 (Nash et al. 2001), WNv has become enzootic in all 48 contiguous states, and has been reported from 96% of counties to date (Centers for Disease Control and Prevention [CDC] 2013). West Nile virus has been detected in 65 species of mosquito in the United States (CDC 2012) and its ability to establish and persist across ecosystems and hosts is illustrated by its extensive distribution (CDC 2013). West Nile virus infection has been reported in 326 avian species (CDC 2013). Among a more scarcely occurring avian guild like the raptors, the CDC Arbornet Surveillance System (1999 to 2004) have documented infection in 36 species (Nemeth et al. 2006), approximately 70% of all raptor species occurring in North America

    West Nile Virus and Ferruginous Hawks (Buteo Regalis) in the Northern Great Plains

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    Emerging infectious diseases (EID) present significant threats to the conservation of global biodiversity (Daszak et al. 2000). Evaluating impacts (spatial, temporal and demographic) of EIDs on sensitive and declining wildlife populations is challenging because quantitative information is usually dependent on estimates rather than counts (Wobeser 2007) and mortality rates are seldom quantified with conventional monitoring (Naugle et al. 2005)

    Resolution of Clinical and Laboratory Abnormalities after Diagnosis of Ventilator-Associated Pneumonia in Trauma Patients

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    Background: Guidelines advise that patients with ventilator-associated pneumonia (VAP) should respond clinically by Day 3 of antibiotics. White blood cell (WBC) count, maximum temperature (Tmax), and PaO2:FIO2 ratio are all said to respond significantly by Day 6. Resolution of abnormalities has not been evaluated in trauma patients. Methods: Retrospective review of trauma patients with VAP. The WBC count, Tmax, and PaO2:FIO2 were evaluated for 16 days after diagnosis. Patients were grouped into uncomplicated VAP, complicated VAP (those with inadequate empirical therapy [IEAT], VAP relapse/superinfection, or acute respiratory distress syndrome), and concurrent infection +VAP (those also infected at another site). Results: There were 126 patients (uncomplicated VAP= 29, complicated VAP = 69, and concurrent infection + VAP = 28). The mean Tmax in patients with uncomplicated VAP decreased significantly from diagnosis to Day 4 (Day 1: 39 – 0.5°C vs. Day 4: 38.6 – 0.7°C; p = 0.028) but never normalized. Their WBC counts and PaO2:FIO2 did not change significantly over the 16-day follow-up and never normalized.When comparing the three groups, the probability of resolving all three abnormalities was not different (p = 0.5). Conclusions: Clinical and laboratory abnormalities in critically injured patients with VAP do not resolve as quickly as suggested in the guidelines. Future studies should evaluate new methods to determine the response to antibiotic therapy in critically injured patients with VAP

    A morphologic and molecular reappraisal of myoepithelial tumors of soft tissue, bone, and viscera with EWSR1 and FUS gene rearrangements

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    Myoepithelial tumors (MET) represent a clinicopathologically heterogeneous group of tumors, ranging from benign to highly aggressive lesions. Although MET arising in soft tissue, bone, or viscera share morphologic and immunophenotypic overlap with their salivary gland and cutaneous counterparts, there is still controversy regarding their genetic relationship. Half of MET of soft tissue and bone harbor EWSR1 or FUS related fusions, while MET arising in the salivary gland and skin often show PLAG1 and HMGA2 gene rearrangements. Regardless of the site of origin, the gold standard in diagnosing a MET relies on demonstrating its "myoepithelial immunophenotype" of positivity for EMA/CK and S100 protein or GFAP. However, the morphologic spectrum of MET in soft tissue and bone is quite broad and the above immunoprofile is nonspecific, being shared by other pathogenetically unrelated neoplasms. Moreover, rare MET lack a diagnostic immunoprofile but shows instead the characteristic gene fusions. In this study, we analyzed a large cohort of 66 MET with EWSR1 and FUS gene rearrangements spanning various clinical presentations, to better define their morphologic spectrum and establish relevant pathologic-molecular correlations. Genetic analysis was carried out by FISH for EWSR1/FUS rearrangements and potential partners, and/or by targeted RNA sequencing. Then, 82% showed EWSR1 rearrangement, while 18% had FUS abnormalities. EWSR1-POU5F1 occurred with predilection in malignant MET in children and young adults and these tumors had nested epithelioid morphology and clear cytoplasm. In contrast, EWSR1/FUS-PBX1/3 fusions were associated with benign and sclerotic spindle cell morphology. Tumors with EWSR1-KLF17 showed chordoma-like morphology. Our results demonstrate striking morphologic-molecular correlations in MET of bone, soft tissue and viscera, which might have implications in their clinical behavior.</p

    Mate Replacement and Alloparental Care in Ferruginous Hawk

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    Alloparental care (i.e., care for unrelated offspring) has been documented in various avian species (Maxson 1978, Smith et al. 1996, Tella et al. 1997, Lislevand et al. 2001, Literak and Mraz 2011). A male replacement mate that encounters existing broods has options, which include alloparental care or infanticide. Infanticide may be beneficial in some species (Rohwer 1986, Kermott et al. 1990), but in long-lived avian species, like the ferruginous hawk (Buteo regalis) that do not renest within a season, infanticide might be detrimental. Adoption and rearing success likely provide direct evidence of competence of replacement mates as potential parents for future seasons, a benefit that might outweigh the investment of time and effort associated with adoption and rearing (after Rohwer 1986). Anticipated mating opportunity at the cost of adoption (Gori et al. 1996, Rohwer et al. 1999) may explain step-parental benevolence and therefore, in such a scenario would enhance individual fitness through subsequent recruitment of related young

    Relayed nuclear Overhauser enhancement sensitivity to membrane Cho phospholipids

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155956/1/mrm28258_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155956/2/mrm28258.pd

    DSM-5 insomnia disorder in pregnancy: associations with depression, suicidal ideation, and cognitive and somatic arousal, and identifying clinical cutoffs for detection

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    STUDY OBJECTIVES: The study had three primary goals. First, we estimated survey-assessed DSM-5 insomnia disorder rates in pregnancy, and described associated sociodemographics, and sleep-wake and mental health symptoms. Second, we derived cutoffs for detecting DSM-5 insomnia disorder using common self-report measures of sleep symptoms. Third, we identified clinically relevant cut-points on measures of nocturnal cognitive and somatic arousal. METHODS: Ninety-nine women (85.9% in the 2nd trimester) completed online surveys including DSM-5 insomnia disorder criteria, the Insomnia Severity Index (ISI), Pittsburgh Sleep Quality Index (PSQI), Presleep Arousal Scale’s Cognitive (PSASC) and Somatic (PSASS) factors, and Edinburgh Postnatal Depression Scale. RESULTS: DSM-5 insomnia disorder rate was 19.2%. Insomnia was associated with depression, suicidality, nocturnal cognitive and somatic arousal, and daytime sleepiness. An ISI scoring method that aligns with DSM-5 criteria yielded excellent metrics for detecting insomnia disorder and good sleep. Regarding quantitative cutoffs, ISI ≥ 10 and ISI ≥ 11 (but not ISI ≥ 15) were supported for detecting DSM-5 insomnia, whereas ISI ≤ 7 and ISI ≤ 9 performed well for detecting good sleep. PSQI cutoff of 5 was supported for detecting insomnia and good sleep. The optimal cutoff for nocturnal cognitive arousal was PSASC ≥ 18, whereas the optimal cutoff for somatic arousal was PSASS ≥ 13. CONCLUSIONS: Insomnia disorder affects a large segment of pregnant women. Empirically derived cutoffs for insomnia, good sleep, cognitive arousal, and somatic arousal may inform case identification and future perinatal sleep research methodology
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