423 research outputs found

    High Resolution Wind Retrieval for Seawinds on QuikSCAT

    Get PDF
    The Sea Winds instrument was designed to provide wind measurements over the oceans with a resolution of 25x25 km per pixel. Through the use of image enhancement algorithms developed at BYU this resolution can be increased to as fine as 2.5x2.5 km. A description of key portions of this high resolution wind retrieval algorithm is given, with a summary of results

    Weed control and overstory reduction improve survival and growth of under‐planted oak and hickory seedlings

    Get PDF
    Weed control and overstory reduction are important silvicultural treatments for improving survival and growth of under‐planted oak and hickory seedlings. Mast‐producing trees in the bottomland forests of the blackland prairie and Post Oak Savannah ecoregions of Texas have declined in abundance. Oaks and hickories have been replaced by more shade‐tolerant species, including green ash (Fraxinus pennsylvanica Marshall) and sugarberry (Celtis laevigata Willd.), which do not produce significant hard mast for priority wildlife species. A split‐plot experiment design was installed on three sites at Richland Creek Wildlife Management Area in Freestone County, Texas, studying the effects of canopy coverage and competition control on survival and growth of bur oak (Quercus macrocarpa Michx.), Shumard oak (Quercus shumardii Buckl.), and pecan (Carya illinoinensis (Wagenh.) K. Koch) seedlings. Uprooting by hogs shortly after planting resulted in greater than 90% mortality of pecan on the two lower elevation sites. Year one survival of Shumard oak was significantly higher than bur oak. However, bur oak was more preferred by hogs than Shumard oak. Year one growth of bur oak was significantly greater than Shumard oak. Severe flooding during the second growing season caused complete mortality on the lower two sites. None of the species were well suited to such prolonged (3–4 months) inundation as seedlings. On the remaining site, density reduction and weed‐barrier mats improved growth and survival while herbaceous weed control with herbicides actually reduced both growth and survival

    Gold substrate-induced single-mode lasing of GaN nanowires

    Get PDF
    We demonstrate a method for mode-selection by coupling a GaN nanowire laser to an underlying gold substrate. Multimode lasing of GaN nanowires is converted to single-mode behavior following placement onto a gold film. A mode-dependent loss is generated by the absorbing substrate to suppress multiple transverse-mode operation with a concomitant increase in lasing threshold of only ∌13%. This method provides greater flexibility in realizing practical single-mode nanowire lasers and offers insight into the design of metal-contacted nanoscale optoelectronics

    Why do Adolescents Seek Online Mental Health Information?

    Get PDF
    Many adolescents avoid seeking psychological help despite the increasing prevalence of mental disorders. The current study investigated whether distress and stigma exhibit differential relationships to decisions to seek online mental health information among a sample of predominantly racial/ethnic minority U.S. adolescents. In this investigation, 174 adolescents (Age: M = 15.90, SD = 0.85, Range = 14−19) completed assessments of help-seeking stigma, psychological distress, and a question asking if they would like to view a website with mental health information. Distress was a statistically significant predictor of decisions to seek online mental health information, but stigma was not. Severely distressed boys were more likely to seek online information than severely distressed girls. Evidence-based online resources may be particularly effective ways to support distressed adolescents

    Integrative Modeling of Quantitative Plasma Lipoprotein, Metabolic, and Amino Acid Data Reveals a Multiorgan Pathological Signature of SARS-CoV-2 Infection.

    Get PDF
    The metabolic effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on human blood plasma were characterized using multiplatform metabolic phenotyping with nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography-mass spectrometry (LC-MS). Quantitative measurements of lipoprotein subfractions, α-1-acid glycoprotein, glucose, and biogenic amines were made on samples from symptomatic coronavirus disease 19 (COVID-19) patients who had tested positive for the SARS-CoV-2 virus (n = 17) and from age- and gender-matched controls (n = 25). Data were analyzed using an orthogonal-projections to latent structures (OPLS) method and used to construct an exceptionally strong (AUROC = 1) hybrid NMR-MS model that enabled detailed metabolic discrimination between the groups and their biochemical relationships. Key discriminant metabolites included markers of inflammation including elevated α-1-acid glycoprotein and an increased kynurenine/tryptophan ratio. There was also an abnormal lipoprotein, glucose, and amino acid signature consistent with diabetes and coronary artery disease (low total and HDL Apolipoprotein A1, low HDL triglycerides, high LDL and VLDL triglycerides), plus multiple highly significant amino acid markers of liver dysfunction (including the elevated glutamine/glutamate and Fischer's ratios) that present themselves as part of a distinct SARS-CoV-2 infection pattern. A multivariate training-test set model was validated using independent samples from additional SARS-CoV-2 positive patients and controls. The predictive model showed a sensitivity of 100% for SARS-CoV-2 positivity. The breadth of the disturbed pathways indicates a systemic signature of SARS-CoV-2 positivity that includes elements of liver dysfunction, dyslipidemia, diabetes, and coronary heart disease risk that are consistent with recent reports that COVID-19 is a systemic disease affecting multiple organs and systems. Metabolights study reference: MTBLS2014

    Interactions between Neuropsychiatric Symptoms and Alzheimer’s Disease Neuroimaging Biomarkers in Predicting Longitudinal Cognitive Decline

    Get PDF
    OBJECTIVE: To examine interactions between Neuropsychiatric symptoms (NPS) with Pittsburgh Compound B (PiB) and fluorodeoxyglucose positron emission tomography (FDG-PET) in predicting cognitive trajectories. METHODS: We conducted a longitudinal study in the setting of the population-based Mayo Clinic Study of Aging in Olmsted County, MN, involving 1581 cognitively unimpaired (CU) persons aged ≄50 years (median age 71.83 years, 54.0% males, 27.5% APOE ɛ4 carriers). NPS at baseline were assessed using the Neuropsychiatric Inventory Questionnaire (NPI-Q). Brain glucose hypometabolism was defined as a SUVR ≀ 1.47 (measured by FDG-PET) in regions typically affected in Alzheimer\u27s disease. Abnormal cortical amyloid deposition was measured using PiB-PET (SUVR ≄ 1.48). Neuropsychological testing was done approximately every 15 months, and we calculated global and domain-specific (memory, language, attention, and visuospatial skills) cognitive z-scores. We ran linear mixed-effect models to examine the associations and interactions between NPS at baseline and z-scored PiB- and FDG-PET SUVRs in predicting cognitive z-scores adjusted for age, sex, education, and previous cognitive testing. RESULTS: Individuals at the average PiB and without NPS at baseline declined over time on cognitive z-scores. Those with increased PiB at baseline declined faster (two-way interaction), and those with increased PiB and NPS declined even faster (three-way interaction). We observed interactions between time, increased PiB and anxiety or irritability indicating accelerated decline on global z-scores, and between time, increased PiB and several NPS (e.g., agitation) showing faster domain-specific decline, especially on the attention domain. CONCLUSIONS: NPS and increased brain amyloid deposition synergistically interact in accelerating global and domain-specific cognitive decline among CU persons at baseline

    Implementation of U.K. Earth system models for CMIP6

    Get PDF
    We describe the scientific and technical implementation of two models for a core set of experiments contributing to the sixth phase of the Coupled Model Intercomparison Project (CMIP6). The models used are the physical atmosphere-land-ocean-sea ice model HadGEM3-GC3.1 and the Earth system model UKESM1 which adds a carbon-nitrogen cycle and atmospheric chemistry to HadGEM3-GC3.1. The model results are constrained by the external boundary conditions (forcing data) and initial conditions.We outline the scientific rationale and assumptions made in specifying these. Notable details of the implementation include an ozone redistribution scheme for prescribed ozone simulations (HadGEM3-GC3.1) to avoid inconsistencies with the model's thermal tropopause, and land use change in dynamic vegetation simulations (UKESM1) whose influence will be subject to potential biases in the simulation of background natural vegetation.We discuss the implications of these decisions for interpretation of the simulation results. These simulations are expensive in terms of human and CPU resources and will underpin many further experiments; we describe some of the technical steps taken to ensure their scientific robustness and reproducibility
    • 

    corecore