111 research outputs found

    The spatial extent of tephra deposition and environmental impacts from the 1912 Novarupta eruption

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    The eruption of Novarupta within the Katmai Volcanic Cluster, south-west Alaska, in June 1912 was the most voluminous eruption of the twentieth century but the distal distribution of tephra deposition is inadequately quantified. We present new syntheses of published tephrostratigraphic studies and a large quantity of previously un-investigated historical records. For the first time, we apply a geostatistical technique, indicator kriging, to integrate and interpolate such data. Our results show evidence for tephra deposition across much of Alaska, Yukon, the northern Pacific, western British Columbia and northwestern Washington. The most distal tephra deposition was observed around 2,500 km downwind from the volcano. Associated with tephra deposition are many accounts of acid deposition and consequent impacts on vegetation and human health. Kriging offers several advantages as a means to integrate and present such data. Future eruptions of a scale similar to the 1912 event have the potential to cause widespread disruption. Historical records of tephra deposition extend far beyond the limit of deposition constrained by tephrostratigraphic records. The distal portion of tephra fallout deposits is rarely adequately mapped by tephrostratigraphy alone; contemporaneous reports of fallout can provide important constraints on the extent of impacts following large explosive eruptions

    Relationship between peripheral airway function and patient-reported outcomes in COPD: a cross-sectional study

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    <p>Abstract</p> <p>Background</p> <p>Health status, dyspnea and psychological status are important clinical outcomes in chronic obstructive pulmonary disease (COPD). However, forced expiratory volume in one second (FEV<sub>1</sub>) measured by spirometry, the standard measurement of airflow limitation, has only a weak relationship with these outcomes in COPD. Recently, in addition to spirometry, impulse oscillometry (IOS) measuring lung resistance (R) and reactance (X) is increasingly being used to assess pulmonary functional impairment.</p> <p>Methods</p> <p>We aimed to identify relationships between IOS measurements and patient-reported outcomes in 65 outpatients with stable COPD. We performed pulmonary function testing, IOS, high-resolution computed tomography (CT), and assessment of health status using the St. George's Respiratory Questionnaire (SGRQ), dyspnea using the Medical Research Council (MRC) scale and psychological status using the Hospital Anxiety and Depression Scale (HADS). We then investigated the relationships between these parameters. For the IOS measurements, we used lung resistance at 5 and 20 Hz (R5 and R20, respectively) and reactance at 5 Hz (X5). Because R5 and R20 are regarded as reflecting total and proximal airway resistance, respectively, the fall in resistance from R5 to R20 (R5-R20) was used as a surrogate for the resistance of peripheral airways. X5 was also considered to represent peripheral airway abnormalities.</p> <p>Results</p> <p>R5-R20 and X5 were significantly correlated with the SGRQ and the MRC. These correlation coefficients were greater than when using other objective measurements of pulmonary function, R20 on the IOS and CT instead of R5-R20 and X5. Multiple regression analyses showed that R5-R20 or X5 most significantly accounted for the SGRQ and MRC scores.</p> <p>Conclusions</p> <p>IOS measurements, especially indices of peripheral airway function, are significantly correlated with health status and dyspnea in patients with COPD. Therefore, in addition to its simplicity and non-invasiveness, IOS may be a useful clinical tool not only for detecting pulmonary functional impairment, but also to some extent at least estimating the patient's quality of daily life and well-being.</p

    Quantum Spacetime Phenomenology

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    I review the current status of phenomenological programs inspired by quantum-spacetime research. I stress in particular the significance of results establishing that certain data analyses provide sensitivity to effects introduced genuinely at the Planck scale. And my main focus is on phenomenological programs that managed to affect the directions taken by studies of quantum-spacetime theories.Comment: 125 pages, LaTex. This V2 is updated and more detailed than the V1, particularly for quantum-spacetime phenomenology. The main text of this V2 is about 25% more than the main text of the V1. Reference list roughly double

    Executive Function in Pediatric Bipolar Disorder and Attention-Deficit Hyperactivity Disorder: In Search of Distinct Phenotypic Profiles

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