31 research outputs found

    Assessing and Analyzing Near-Surface Radar Snow Accumulation Layers at Summit, Greenland

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    High vertical-resolution 0.5&mdash2 GHz frequency-modulated continuous-wave radar data collected near Summit on the Greenland Ice Sheet reveal continuous horizons connecting the GRIP and GISP2 deep ice cores. Traced radar horizons to 150 meters depth are compared to physical properties, age-depth relationships, and accumulation rates from ice cores near Summit. Having established the radar horizons as annual accumulation markers, a 350-year record of accumulation rate is derived and analyzed spatially and temporally. Accumulation characteristics such as spatial noise, long-term accumulation rate, and climate fluctuations are determined. Averaging accumulation across 1000&mdash2000 m eliminates most spatial noise associated with small-scale surface perturbations, providing a good approximation of the local accumulation rate. Overall, a detailed record of accumulation is gained, indicating that near-surface radar surveys can take the place of shallow ice cores for examining accumulation history, improving knowledge of spatial and temporal variability, spatial and temporal noise, and other accumulation characteristics

    Disaster Mitigation Programs in Tulsa, Oklahoma: An Examination of Organizational Survival

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    This study uses qualitative analysis to examine how Tulsa Project Impact, a formalized emergent citizen group, survived a major external environmental change. Tulsa Project Impact was formed from FEMA Project Impact, a federal grant that provided funding for disaster mitigation programs in local communities. This grant ended abruptly in 2000, leaving managers in Tulsa searching for ways to continue the city's mitigation programs. Using qualitative interviews and document analysis, the conditions for organizational survival are examined. Based upon the data gathered throughout the course of this study, it is apparent that three conditions affected Tulsa Project Impact's ability to survive the environmental change. The conditions that affected organizational survival were organizational goal transformation, professional networks, and resource mobilization. Tulsa Project Impact was able to survive the change because they established a flexible, broad goal that allowed managers to expand the scope of the organization, and to pursue new grant opportunities. If the organization had narrow goals, new programs may not have been added because they would not be aligned with existing goals. In addition, the networks the organization had built were critical to survival. Tulsa Project Impact used networks to recruit new partners to support their programs. Perhaps most vital to the survival of Tulsa Project Impact was their ability to mobilize resources. The programs offered were funded from grants and donations. Tulsa Project Impact established a non-profit agency, which allowed for acquisition of donations and non-profit grants. This organization was vital after FEMA Project Impact ended, and allowed Tulsa's organization to survive. The combination of organizational goal transformation, professional networks, and resource mobilization allowed Tulsa Project Impact to survive after FEMA Project Impact ended.Fire Protection & Safety Technology Progra

    Recent Accumulation Variability in Northwest Greenland from Ground-Penetrating Radar and Shallow Cores along the Greenland Inland Traverse

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    Accumulation is a key parameter governing the mass balance of the Greenland ice sheet. Several studies have documented the spatial variability of accumulation over wide spatial scales, primarily using point data, remote sensing or modeling. Direct measurements of spatially extensive, detailed profiles of accumulation in Greenland, however, are rare. We used 400 MHz ground-penetrating radar along the 1009 km route of the Greenland Inland Traverse from Thule to Summit during April and May of 2011, to image continuous internal reflecting horizons. We dated these horizons using ice-core chemistry at each end of the traverse. Using density profiles measured along the traverse, we determined the depth to the horizons and the corresponding water-equivalent accumulation rates. The measured accumulation rates vary from ~0.1 m w.e. a–1 in the interior to ~0.7 m w.e. a–1 near the coast, and correspond broadly with existing published model results, though there are some excursions. Comparison of our recent accumulation rates with those collected along a similar route in the 1950s shows a ~10% increase in accumulation rates over the past 52 years along most of the traverse route. This implies that the increased water vapor capacity of warmer air is increasing accumulation in the interior of Greenland

    Paclitaxel, carboplatin, and capecitabine (TCX) with and without radiation in locally advanced and metastatic distal esophageal and esophagogastric junction cancer: A single-center retrospective review

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    197 Background: Toxicities of the active triple-drug DCF regimen (docetaxel, cisplatin and 5-FU) in gastric cancer limit its broad use and general acceptance as first-line therapy. To improve the toxicity profile of triple-drug therapy, distal esophageal and esophagogastric junction (DE-EGJ) poorly differentiated and moderately differentiated adenocarcinoma patients were treated with TCX. This single-center retrospective review is reported for patients treated between 2005 and 2013. Methods: Patients with DE-EGJ adenocarcinoma were treated with capecitabine (850 mg/m2 5 out of 7 or 14 out of 21 days), carboplatin (AUC 5) and paclitaxel (175 mg/m2) every 3 weeks. Those with locally advanced disease received concomitant radiation therapy (50.4 Gy using 3D approach) during the first 2 cycles. Dose reductions (25-50%), delay of therapy and hospitalizations for disease and treatment-related Grades 3/4 toxicities were recorded. Growth factors were prescribed reactively. Kaplan-Meier statistics were used for survival analyses. The institutional tumor registry data provided the historical median survival. Results: Thirty-one males and 3 females (median age 56, range 37-82) with locally advanced (N=17) and metastatic (N=17) disease were included. Median overall survivals are shown below. Two patients were admitted for neutropenic fever and 7 total hospitalizations occurred. Conclusions: A triple-drug combination first-line regimen (TCX) with and without radiation in DE-EGJ cancer is active, and associated with a manageable toxicity profile. The median survival of 15.8 months in patients with metastatic disease treated with TCX compares favorably with the DCF regimen (9.2 mos), the EOX regimen (11.2 mos) as well as institutional historical controls. Our data suggests that future prospective trials evaluating triple-drug regimens in combination with targeted therapy may be feasible in patients with esophageal and gastric adenocarcinoma. [Table: see text

    Atmospheric blocking drives recent albedo change across the western Greenland ice sheet percolation zone

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    Greenland Ice Sheet (GrIS) albedo has decreased over recent decades, contributing to enhanced surface melt and mass loss. However, it remains unclear whether GrIS darkening is due to snow grain size increases, higher concentrations of light-absorbing impurities (LAIs), or a combination. Here, we assess albedo controls in the western GrIS percolation zone using in situ albedo, LAI, and grain size measurements. We find a significant correlation between albedo and snow grain size (p \u3c 0.01), but not with LAIs. Modeling corroborates that LAI concentrations are too low to significantly reduce albedo, but larger grain sizes could reduce albedo by at least ∼3%. Strong atmospheric blocking increases grain sizes and reduces albedo through increased surface temperature, fewer storms, and higher incoming shortwave radiation. These findings clarify the mechanisms by which anomalously strong blocking contributed to recent GrIS albedo decline and mass loss, highlighting the importance of improving projections of future blocking
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