222 research outputs found

    Detection of the 2010 Chilean Tsunami Using Satellite Altimetry

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    Tsunamis are difficult to detect and measure in the open ocean because the wave amplitude is much smaller than it is closer to shore. An effective early warning system, however, must be able to observe an impending tsunami threat far away from the shore in order to provide the necessary lead-time for coastal inhabitants to find safety. Given the expansiveness of the ocean, sensors capable of detecting the tsunami must also have very broad areal coverage. The 2004 Sumatra-Andaman tsunami was definitively detected in the open ocean from both sea surface height and sea surface roughness measurements provided by satellite altimeters. This tsunami, however, was exceptionally strong and questions remain about the ability to use such measurements for the detection of weaker tsunamis. Here we study the 2010 Chilean tsunami and demonstrate the ability to detect the tsunami in the open ocean. Specifically, we analyze the utility of filtering in extracting the tsunami signal from sea surface height measurements, and, through the use of statistical analyses of satellite altimeter observations, we demonstrate that the 2010 Chilean tsunami induced distinct and detectable changes in sea surface roughness. While satellite altimeters do not provide the temporal and spatial coverage necessary to form the basis of an effective early warning system, tsunami-induced changes in sea surface roughness can be detected using orbiting microwave radars and radiometers, which have a broad surface coverage across the satellite ground track

    Long-term mineral transformation of Ca-rich oil shale ash waste

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    Power generation and other industries using solid fossil fuels like coal, lignite, oil shale and peat are responsible for producing large quantities of solid residues that are often chemically reactive and/or unstable and are disposed in holding ponds and deposition sites. Stability and long-term behaviour of such deposits are typically studied in short-term laboratory experiments that cannot describe nor predict long-term changes taking place in these materials. Here, we study long-term (>40 years) transformations, in highly alkaline conditions, of the Ca-rich ash deposit in Estonia composed of oil shale processing residues from the Eesti power plant. Detailed mineralogical, chemical and micromorphological analyses using X-ray diffraction, X-ray fluorescence, 29Si nuclear magnetic resonance, scanning electron microscopy and other methods were applied in order to identify the composition of the waste with a focus on formation and transformation of semicrystalline phases in the deposit. The results show progressive formation of calcium-silicate-hydrate (C-S-H) type phase at the expense of silicate minerals and amorphous glass phases with increasing depth and age of the sediments, from about 25% in the upper part of the depository to over 60% in the oldest-deepest part. This demonstrates that over time the high alkalinity of the ash is responsible for initiating natural alkali-activation. The formation of C-S-H-type phases increases the mechanical strength of the sediment and ensures long-term stability of waste deposits. These findings may encourage the use of these ashes in binder or other construction material production or as construction aggregates

    Linguistics

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    Contains reports on five research projects.National Institute of Mental Health (Grant 5 PO1 MH-13390-04

    Examining Factors Associated with the Use of Face Coverings during COVID-19: A Survey of Shoppers in Greater Grand Forks, Minnesota and North Dakota

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    Despite the availability of COVID-19 vaccines, the pandemic’s persistence and recent spikes in cases have heightened the need for the promotion of protective behaviors notably, the continued use of face coverings (or ‘masks’ in the common parlance for COVID-related face coverings). Effective messaging on mask use is essential to more fully resonate with individuals and their shared communities. Studies covering rural or mostly-urban regions in the U.S. are sparse. Accordingly, an interdisciplinary team of social work and public health researchers explored mask wearing behaviors in a small, urban metro community consisting of two cities spanning North Dakota and Minnesota that serves a mostly rural region. Chi-square tests for independence revealed nuanced gender and age-based differences in face covering usage. Significant factors in mask usage included satisfaction with available information and related public education efforts, and approval from people perceived to be important. Findings suggest the value of utilizing parasocial interactions to promote protective behaviors such as face covering use. This paper discusses additional implications

    Immunoglobulin expression in the endoplasmic reticulum shapes the metabolic fitness of B lymphocytes

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    The major function of B lymphocytes is to sense antigens and to produce protective antibodies after activation. This function requires the expression of a B-cell antigen receptor (BCR), and evolutionary conserved mechanisms seem to exist that ensure that B cells without a BCR do not develop nor survive in the periphery. Here, we show that the loss of BCR expression on Burkitt lymphoma cells leads to decreased mitochondrial function and impaired metabolic flexibility. Strikingly, this phenotype does not result from the absence of a classical Syk-dependent BCR signal but rather from compromised ER expansion. We show that the reexpression of immunoglobulins (Ig) in the absence of the BCR signaling subunits Igα and Igβ rescues the observed metabolic defects. We demonstrate that immunoglobulin expression is needed to maintain ER homeostasis not only in lymphoma cells but also in resting B cells. Our study provides evidence that the expression of BCR components, which is sensed in the ER and shapes mitochondrial function, represents a novel mechanism of metabolic control in B cells
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