Performance Evaluation of Inverted Tee (IT) Bridge System

The Inverted Tee (IT) girder bridge system was originally developed in 1996 by the University of Nebraska–Lincoln (UNL) researchers and Nebraska Department of Transportation (NDOT) engineers. This bridge system currently accounts for over 110 bridges in Nebraska used for both state highways and local county roads. Extensive longitudinal and transverse deck cracking have been observed and noted in numerous bridge inspection reports. Since the IT girder bridge system is relatively new, limited data and knowledge exist on its structural performance and behavior. This study evaluates the IT girder bridge system by conducting twenty field observations as well as recording accelerometer, strain gauge, and LVDT time histories and lidar scans for a selected subset of these bridges and then a three-dimensional finite element analysis (FEA) was conducted. The field observations included visual inspection for damage and developing deck crack maps to identify a trend for the damage. System identification of the bridge deck and girders helped investigate the global and local structural responses, respectively. Operational modal analysis quantified the natural frequencies, damping ratios, and operational deflected shapes for the instrumented IT girder bridges. These results helped diagnose the reason for the longitudinal deck cracking. The IT girders respond non- uniformly for the first operational deflected shape and independently for higher modes. Two comparable bridges, namely one slab and one NU girder bridge, were instrumented to verify and demonstrate that the IT girder behavior is unique. An advanced geospatial analysis was conducted for the IT girder bridges to develop lidar depth maps of the deck and girders elevations. These depth maps help identify locations of potential water/chloride penetration and girders set at various elevations and/or where the deck thickness is non-uniform. Live load tests helped quantify the transverse dynamic behavior of the bridge girders. Quantifying the transverse dynamic behavior helped validate the source of longitudinal deck cracking in IT girder bridges, which was determined to be the differential deflection between adjacent IT girders. The FEA analysis was conducted to evaluate the live load moment and shear distribution factors and compare that to the predicted values calculated from the AASHTO Standard and LRFD bridge design specifications. The comparison indicated that the predicted distribution factors were conservative. Also, interviews with IT bridge producers and contractors were conducted to determine production and construction advantages and challenges of this bridge system

Weight and Body Image Perceptions in Nutrition and Dietetics University Students

Stereotypical and prejudicial attitudes towards people considered overweight or obese are documented in professionals ranging from physicians, nurses, fitness and general nutrition professionals, and registered dietitian nutritionists (RDN) and may introduce barriers to equitable care. To identify the prevalence of anti-fat attitudes (AFA); fat phobia (FPS); and body appreciation scores (BA) in nutrition and dietetics’ students (ND) and non-nutrition and dietetics’ students (NND) through a cross-sectional design. During 2018, students (n=297) from two California State Universities completed a survey including three validated instruments. Additionally, height, weight, and waist circumference were collected using NHANES procedures. A series of ANCOVA’s and correlation coefficients were computed. Significant differences existed in BA between ND (M=3.61, SD=0.66) and NND students (M=3.81, SD=0.70); t(288) = 2.49, p=0.013. Scores indicated existing anti-fat attitudes and fat phobia. Significant positive correlations existed between FPS and anthropometrics. Weight related perceptions were identified. A need exists for a fundamental evidence-based training specifically focused on knowledge and awareness related to health metrics and social justice pedagogy to help RDN work unbiasedly with patients of all shapes

Do false positive thallium-201 scans lead to unnecessary catheterization? outcome of patients with perfusion defects on quantitative planar thallium-201 scintigraphy

AbstractObjectives. We postulated that artifactually abnormal thallium-201 scans are well identified at the time of initial clinical interpretation by experienced readers and do not lead to unnecessary coronary angiography.Background. Exercise thallium-201 scintigraphy employing quantitative imaging techniques has yielded sensitivity and specificity values of 80% to 90%. There are image artifacts, such as breast shadows, and variants of normal that, if not correctly identified, can lead to a high false positive rate for detection of coronary artery disease.Methods. Data from 338 consecutive patients with one or more focal thallium-201 defects on quantitative planar Images were reviewed. All patients had undergone symptom-limited exercise scintigraphy and were classified as having either artifactual or nonartifactual thallium-201 defects after review of clinical reports.Results. Of the 265 patients with defects judged to be nonartifactual on clinical readings, 167 underwent coronary angiography, which demonstrated significant coronary artery disease (≥50% stenosis) in 161 (96%) and normal findings in 6. Four of the latter six had documented prior myocardial infarction. The remaining 73 patients (85% female) had thallium-201 defects deemed to be artifactual on clinical readings, chiefly as a result of breast (66%) and diaphragmatic (8%) attenuation or variants of normal (26%). Only 4 (5%) of the 73 patients underwent subsequent coronary angiography; none had coronary artery disease. One had aortic stenosis and two had variant angina. Follow-up (mean 20 ± 2 months) of the 69 patients in this group who did not undergo coronary angiography revealed no deaths and one nonfatal non-Q wave myocardial infarction.Conclusions. Artifactual defects on quantitative planar thallium-201 scintigraphy are well recognized by experienced interpreters and do not result in a high false positive rate leading to unnecessary cardiac catheferization. The incidence of coronary artery disease is high in patients with thallium-201 defects judged to be nonartifactual, and many patients with perfusion defects and angiographically normal coronary arteries have organic heart disease

A new method for imaging nuclear threats using cosmic ray muons

Muon tomography is a technique that uses cosmic ray muons to generate three dimensional images of volumes using information contained in the Coulomb scattering of the muons. Advantages of this technique are the ability of cosmic rays to penetrate significant overburden and the absence of any additional dose delivered to subjects under study above the natural cosmic ray flux. Disadvantages include the relatively long exposure times and poor position resolution and complex algorithms needed for reconstruction. Here we demonstrate a new method for obtaining improved position resolution and statistical precision for objects with spherical symmetry

First Fruits of the Spitzer Space Telescope: Galactic and Solar System Studies

This article provides a brief overview of the Spitzer Space Telescope and discusses its initial scientific results on galactic and solar system science.Comment: Review article to appear in slightly different format in Vol.44 of Annual Reviews of Astronomy and Astrophysics, 200

Genetic microheterogeneity and phenotypic variation of Helicobacter pylori arginase in clinical isolates

BACKGROUND: Clinical isolates of the gastric pathogen Helicobacter pylori display a high level of genetic macro- and microheterogeneity, featuring a panmictic, rather than clonal structure. The ability of H. pylori to survive the stomach acid is due, in part, to the arginase-urease enzyme system. Arginase (RocF) hydrolyzes L-arginine to L-ornithine and urea, and urease hydrolyzes urea to carbon dioxide and ammonium, which can neutralize acid. RESULTS: The degree of variation in arginase was explored at the DNA sequence, enzyme activity and protein expression levels. To this end, arginase activity was measured from 73 minimally-passaged clinical isolates and six laboratory-adapted strains of H. pylori. The rocF gene from 21 of the strains was cloned into genetically stable E. coli and the enzyme activities measured. Arginase activity was found to substantially vary (>100-fold) in both different H. pylori strains and in the E. coli model. Western blot analysis revealed a positive correlation between activity and amount of protein expressed in most H. pylori strains. Several H. pylori strains featured altered arginase activity upon in vitro passage. Pairwise alignments of the 21 rocF genes plus strain J99 revealed extensive microheterogeneity in the promoter region and 3' end of the rocF coding region. Amino acid S232, which was I232 in the arginase-negative clinical strain A2, was critical for arginase activity. CONCLUSION: These studies demonstrated that H. pylori arginase exhibits extensive genotypic and phenotypic variation which may be used to understand mechanisms of microheterogeneity in H. pylori

The management of depressed elderly care recipients : family perspectives on the skills of professional carers

Recent studies have identified high levels of depression among older people, both those in their own homes and those in residential care. With the world\u27s population ageing, it is timely for health service providers to consider how the escalating population of depressed elderly people will be managed. Although treating general practitioners may be the health professionals most expected to detect, treat, and monitor depression among the elderly, professional carers are well placed to assist in the detection and monitoring of the disorder. This study conducted individual interviews with 15 family members of depressed aged-care recipients to determine their perceptions of the skills and knowledge of depression of professional carers. Family members reported that carers are more likely to avoid than engage with their clients about depressive symptomatology and do not communicate their concerns with managers or general practitioners (GPs). Family members believed that, in general, professional carers were undertrained in these areas. The implications of these findings for health service planning and staff training are discussed. <br /