Fiber Scanning Array for 3 Dimensional Topographic Imaging

We report on the design and development of a fiber optic scanning 3-D LIDAR employing a switched fiber array. This design distributes ns length laser pulses over a sample field, collects the return pulses, and assembles them into a 3-D image. This instrument is a reduced size version consisting of 35 beams, and will serve as a proof-of-principle demonstration for a planned 1000 beam instrument for Earth and planetary topographical missions

Surface Area as a Predictor of Sample Preservation in Fossil Coral Species

Undergraduate Research Opportunities Program (UROP), Earth & Environmental Sciences, University of Minnesota DuluthRecords of sea level are important for scientists studying climate and geology in the past. Sea level is correlated with how much water is stored in glaciers and ice sheets, which indicates what the climate was like at that time. Past climate records are the key to understanding the future as Earth's climate changes. One method of documenting past sea level is with radiometric uranium-thorium (U-Th) dating of fossil corals. Corals make a good proxy for sea level because they need to grow near the surface of the water, where light is most abundant. Coral concentrate 238U from seawater in their skeleton (Gallup, 2015). Over time, 238U decays to 234U and then to 230Th at a predictable rate. When they first form, corals do not contain any 230Th, because it is insoluble. Thus, the concentration of 230Th in fossil coral skeletons allows us to determine their ages (Gallup, 2015). The elevation that the sample was taken from is then presumably the sea level at the time that coral was alive. In some cases, the coral is at a higher elevation due to tectonic uplift, but this can be corrected for. It's important for the sea level record to be accurate, since it serves as a reference for other research. Thus, it's crucial that U-Th dating methods be as accurate as possible. However, coral fossils are susceptible to alteration after their deposition, which can cause remobilization of 238U and 230Th (Gallup, 2015). The result is a shift in the apparent age of the sample. The quality of the sample can be inferred by looking at the ratio of 234U to its parent, 238U. The ratio at the time of deposition, the initial 234U value, can be calculated from the ratio at the time of analysis. How far it is from the accepted value for seawater at the time of deposition is an indicator of sample quality. Corals with a larger surface area are more susceptible to alteration, since they have more area for chemical and physical weathering. Five different types of coral, most notably Porites, Favids, and Leptids, were studied. Out of these, Porites has highest surface area (El-Sorogy, et. al, 2013), and is therefore more susceptible to alteration over time

SLICER Airborne Laser Altimeter Characterization of Canopy Structure and Sub-canopy Topography for the BOREAS Northern and Southern Study Regions: Instrument and Data Product Description

SLICER data were acquired in support of BOREAS at all of the TF sites in the SSA and NSA, and along transects between the study areas. Data were acquired on 5 days between 18-Jul and 30-Jul-1996. Each coverage of a tower site is typically 40 km in length, with a minimum of 3 and a maximum of 10 lines across each tower oriented in a variety of azimuths. The SLICER data were acquired simultaneously with ASAS hyperspectral, multiview angle images. The SLICER Level 3 products consist of binary files for each flight line with a data record for each laser shot composed of 13 parameters and a 600-byte waveform that is the raw record of the backscatter laser energy reflected from Earth's surface. The SLICER data are stored in a combination of ASCII and binary data files

The treatment of amiodarone-induced hyperthyroidism. Is there a place for surgery?

In many instances amiodarone-induced hyperthyroidism has been reported as mild, thyroid functions returning to normal after discontinuation of the drug. Nevertheless, life-threatening amiodarone-induced thyrotoxicosis has also been described. Conventional treatments such as with antithyroid drugs (Thionamide) and corticosteroids are essentially ineffective or fail to stop the dramatic course of the thyroid crisis. This limited efficacy of medical therapy, particularly in patients with previously--neglected or unknown--thyroid disease, prompted us to intervene surgically. We report a series of six patients who underwent total or nearly total thyroidectomy as first line therapy for four of them. Surgery resulted in rapid resolution of thyrotoxicosis with an uneventful postoperative course. This approach has the advantage of immediate and safe efficacy, low risk of relapse and finally, appears to be the only antithyroid treatment that permits continued therapy with amiodarone

The Arctic Boundary Layer Expedition (ABLE 3A): July–August 1988

The Arctic Boundary Layer Expedition (ABLE 3A) used measurements from ground, aircraft, and satellite platforms to characterize the chemistry and dynamics of the lower atmosphere over Arctic and sub-Arctic regions of North America during July and August 1988. The primary objectives of ABLE 3A were to investigate the magnitude and variability of methane emissions from the tundra ecosystem, and to elucidate factors controlling ozone production and destruction in the Arctic atmosphere. This paper reports the experimental design for ABLE 3A and a summary of results. Methane emissions from the tundra landscape varied widely from −2.1 to 426 mg CH4 m−2 d−1. Soil moisture and temperature were positively correlated with methane emission rates, indicating quantitative linkages between seasonal climate variability and soil metabolism. Enclosure flux measurement techniques, tower-based eddy correlation, and airborne eddy correlation flux measurements all proved robust for application to methane studies in the tundra ecosystem. Measurements and photochemical modeling of factors involved in ozone production and destruction validated the hypothesized importance of low NOx concentrations as a dominant factor in maintaining the pristine Arctic troposphere as an ozone sink. Stratospheric intrusions, long-range transport of mid-latitude pollution, forest fires, lightning, and aircraft are all potential sources of NOx and NOy to Arctic and sub-Arctic regions. ABLE 3A results indicate that human activities may have already enhanced NOy inputs to the region to the extent that the lifetime of O3 against photochemical loss may have already doubled. A doubling of NOx concentration from present levels would lead to net photochemical production of O3 during summer months in the Arctic (Jacob et al., this issue (a)). The ABLE 3A results indicate that atmospheric chemical changes in the northern high latitudes may serve as unique early warning indicators of the rates and magnitude of global environmental change.Engineering and Applied Science