2,656 research outputs found
Lest We Forget The Passage from Africa into the Twenty-First Century
No full textLest We Forget offers a three-dimensional, interactive look at black history in America from slavery to the Civil Rights Era, Barack Obama's presidency, and the foundation of Black Lives Matter.Cover -- Half Title -- Title -- Copyright -- TABLE OF CONTENTS -- PART ONE: LEST WE FORGET THE PASSAGE FROM AFRICA TO SLAVERY AND EMANCIPATION -- PART TWO: FREEDOM'S CHILDREN THE PASSAGE FROM EMANCIPATION TO THE GREAT MIGRATION -- PART THREE: WE SHALL NOT BE MOVED THE PASSAGE FROM THE GREAT MIGRATION INTO THE TWENTY-FIRST CENTURY -- AFTERWORD -- TRANSCRIPTIONS -- ENDNOTES -- ACKNOWLEDGMENTS -- ABOUT THE AUTHOR -- IMAGE CREDITSLest We Forget offers a three-dimensional, interactive look at black history in America from slavery to the Civil Rights Era, Barack Obama's presidency, and the foundation of Black Lives Matter.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
Lest we forget : world war stories, /
No full text(viii, 339 pages) : frontispiece, illustrations, portraits, facsimiles.Print version record
5833: Patrick McVey's Photograph
No full textPatrick McVey was severely injured in action during the war.
The photograph provided shows McVey (left) with two others, who were killed in action.</p
Determining the Origins of Advective Heat Transport Convergence Variability in the North Atlantic
No full textA recent state estimate covering the period 1992–2010 from the Estimating the Circulation and Climate of the Ocean (ECCO) project is utilized to quantify the roles of air–sea heat fluxes and advective heat transport convergences in setting upper-ocean heat content anomalies H in the North Atlantic Ocean on monthly to interannual time scales. Anomalies in (linear) advective heat transport convergences, as well as Ekman and geostrophic contributions, are decomposed into parts that are due to velocity variability, temperature variability, and their covariability. Ekman convergences are generally dominated by variability in Ekman mass transports, which reflect the instantaneous response to local wind forcing, except in the tropics, where variability in the temperature field plays a significant role. In contrast, both budget analyses and simple dynamical arguments demonstrate that geostrophic heat transport convergences that are due to temperature and velocity variability are anticorrelated, and thus their separate treatment is not insightful. In the interior of the subtropical gyre, the sum of air–sea heat fluxes and Ekman heat transport convergences is a reasonable measure of local atmospheric forcing, and such forcing explains the majority of H variability on all time scales resolved by ECCO. In contrast, in the Gulf Stream region and subpolar gyre, ocean dynamics are found to be important in setting H on interannual time scales. Air–sea heat fluxes damp anomalies created by the ocean and thus are not set by local atmospheric variability.United States. National Oceanic and Atmospheric Administration (Grant NA10OAR4310199)United States. National Oceanic and Atmospheric Administration (Grant NA10OAR4310134)United States. National Oceanic and Atmospheric Administration (Grant NA10OAR4310135)National Oceanographic Partnership Program (U.S.) (United States. National Aeronautics and Space Administration Grant NNX08AV89G
A Comparison of Atmospheric Reanalysis Surface Products over the Ocean and Implications for Uncertainties in Air–Sea Boundary Forcing
No full textThis paper investigates the uncertainties related to atmospheric fields from reanalysis products used in forcing ocean models. Four reanalysis products, namely from 1) the interim ECMWF Re-Analysis (ERA-Interim), 2) version 2 of the Common Reference Ocean–Ice Experiments (CORE2), 3) the 25-Year Japanese Reanalysis Project (JRA-25), and 4) NCEP–NCAR, are evaluated against satellite-derived observations for eight different fields (zonal and meridional winds, precipitation, specific humidity, continental discharge, surface air temperature, and downwelling longwave and shortwave radiation fluxes). No single product is found to agree better in all fields with satellite-derived observations. Reanalysis products are mostly comparable to each other because of their similar physical assumptions and assimilation of common observations. Adjusted atmospheric fields from the Estimating the Circulation and Climate of the Ocean (ECCO) optimizations are also in agreement with other reanalysis products. Time-mean and time-variable errors are estimated separately and mapped globally in space, based on 14-day average fields to focus on monthly to interannual periods. Time-variable errors are larger in comparison to the signal than time-mean errors for most fields, thus justifying the need to separate them for studying uncertainties as well as formulating optimization procedures. Precipitation and wind stress fields show significant time-mean and time-variable errors whereas downwelling radiation, air temperature, and humidity fields show small time-mean errors but large time-variable errors, particularly in the tropics. Uncertainties based on evaluating multiple products presented here are considerably larger than uncertainties based on single product pairs.National Science Foundation (U.S.) (Grant ARC-1022733
Low-Frequency SST and Upper-Ocean Heat Content Variability in the North Atlantic
No full textA recent state estimate covering the period 1992–2010 from the Estimating the Circulation and Climate of the Ocean (ECCO) project is utilized to quantify the upper-ocean heat budget in the North Atlantic on monthly to interannual time scales (seasonal cycle removed). Three novel techniques are introduced: 1) the heat budget is integrated over the maximum climatological mixed layer depth (integral denoted as H), which gives results that are relevant for explaining SST while avoiding strong contributions from vertical diffusion and entrainment; 2) advective convergences are separated into Ekman and geostrophic parts, a technique that is successful away from ocean boundaries; and 3) air–sea heat fluxes and Ekman advection are combined into one local forcing term. The central results of our analysis are as follows: 1) In the interior of subtropical gyre, local forcing explains the majority of H variance on all time scales resolved by the ECCO estimate. 2) In the Gulf Stream region, low-frequency H anomalies are forced by geostrophic convergences and damped by air–sea heat fluxes. 3) In the interior of the subpolar gyre, diffusion and bolus transports play a leading order role in H variability, and these transports are correlated with low-frequency variability in wintertime mixed layer depths.United States. National Oceanic and Atmospheric Administration (NOAA Grant NA10OAR4310135)United States. National Oceanic and Atmospheric Administration (NOPP/NASA Grant NNX08AV89G)United States. National Oceanic and Atmospheric Administration (NA13OAR4310134 (Climate Variability and Predictability))United States. National Oceanic and Atmospheric Administration (NOAA Grant NA10OAR4310199)United States. National Aeronautics and Space Administration (NASA Physical Oceanography Program
Solving eigenvalue response matrix equations with nonlinear techniques
No full textThis paper presents new algorithms for use in the eigenvalue response matrix method (ERMM) for reactor eigenvalue problems. ERMM spatially decomposes a domain into independent nodes linked via boundary conditions approximated as truncated orthogonal expansions, the coefficients of which are response functions. In its simplest form, ERMM consists of a two-level eigenproblem: an outer Picard iteration updates the k-eigenvalue via balance, while the inner λ -eigenproblem imposes neutron balance between nodes. Efficient methods are developed for solving the inner λ-eigenvalue problem within the outer Picard iteration. Based on results from several diffusion and transport benchmark models, it was found that the Krylov-Schur method applied to the λ -eigenvalue problem reduces Picard solver times (excluding response generation) by a factor of 2–5. Furthermore, alternative methods, including Picard acceleration schemes, Steffensen’s method, and Newton’s method, are developed in this paper. These approaches often yield faster k-convergence and a need for fewer k-dependent response function evaluations, which is important because response generation is often the primary cost for problems using responses computed online (i.e., not from a precomputed database). Accelerated Picard iteration was found to reduce total computational times by 2–3 compared to the unaccelerated case for problems dominated by response generation. In addition, Newton’s method was found to provide nearly the same performance with improved robustness
Vertical Redistribution of Oceanic Heat Content
No full textEstimated values of recent oceanic heat uptake are on the order of a few tenths of a W m[superscript −2], and are a very small residual of air–sea exchanges, with annual average regional magnitudes of hundreds of W m[superscript −2]. Using a dynamically consistent state estimate, the redistribution of heat within the ocean is calculated over a 20-yr period. The 20-yr mean vertical heat flux shows strong variations in both the lateral and vertical directions, consistent with the ocean being a dynamically active and spatially complex heat exchanger. Between mixing and advection, the two processes determining the vertical heat transport in the deep ocean, advection plays a more important role in setting the spatial patterns of vertical heat exchange and its temporal variations. The global integral of vertical heat flux shows an upward heat transport in the deep ocean, suggesting a cooling trend in the deep ocean. These results support an inference that the near-surface thermal properties of the ocean are a consequence, at least in part, of internal redistributions of heat, some of which must reflect water that has undergone long trajectories since last exposure to the atmosphere. The small residual heat exchange with the atmosphere today is unlikely to represent the interaction with an ocean that was in thermal equilibrium at the start of global warming. An analogy is drawn with carbon-14 “reservoir ages,” which range from over hundreds to a thousand years.National Science Foundation (U.S.) (Grant OCE-0961713)United States. National Oceanic and Atmospheric Administration (Grant NA10OAR4310135
Multimodal Analgesia for Spine Surgery: Does the Intraoperative Opioid Dose Matter?
No full textAuthor Contributions: Patrice Forget: This author wrote the first draft of the manuscript, contributed to the writing of the manuscript, approved the final version of this article and has read, and confirmed meeting the ICMJE criteria for authorship. Juan P. Cata: This author contributed to the writing of the manuscript, approved the final version of this article and has read, and confirmed meeting the ICMJE criteria for authorship. Funding: The authors received no specific funding for this work.Peer reviewe
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