1,889 research outputs found

    From: William Curry

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    Violence and horror : the anti-technology of subjectivity.

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    This thesis is about graphic representations of violence and subjectivity. Simply stated, the violence in many recent horror films is motivated by a nihilism resulting from frustration with the inadequacy of contemporary subjectivity. I want to explore the potential such representations have for providing a means of radically undermining the contemporary category of subjectivity. This subversion is due to what I call the inverted mirror stage effect in combination with a particular dislocation of the audience that is associated with the spectacle of violence displayed in contemporary, or postmodern, horror films. My theoretical approach is a cultural materialist psychoanalytic one that facilitates the traversal of the gap between individual and society by focusing attention not merely on society as a product of individuals, or vice versa, but instead upon the dynamic interaction of the two. Also, this essay draws upon the work of several feminist film theorists, including Carol J. Clover, Judith Halberstam, and Laura Mulvey

    Determination and impact of surface radiative processes for TOGA COARE

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    Experiments using atmospheric general circulation models have shown that the atmospheric circulation is very sensitive to small changes in sea surface temperature in the tropical western Pacific Ocean warm pool region. The mutual sensitivity of the ocean and the atmosphere in the warm pool region places stringent requirements on models of the coupled ocean atmosphere system. At present, the situation is such that diagnostic studies using available data sets have been unable to balance the surface energy budget in the warm pool region to better than 50 to 80 W/sq m. The Tropical Ocean Global Atmosphere (TOGA) Coupled Ocean Atmosphere Response Experiment (COARE) is an observation and modelling program that aims specifically at the elucidation of the physical process which determine the mean and transient state of the warm pool region and the manner in which the warm pool interacts with the global ocean and atmosphere. This project focuses on one very important aspect of the ocean atmosphere interface component of TOGA COARE, namely the temporal and spatial variability of surface radiative fluxes in the warm pool region

    Florida Current surface temperature and salinity variability during the last millennium

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    Author Posting. © American Geophysical Union, 2006. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography, 21 (2006): PA2009, doi:10.1029/2005PA001218.The salinity and temperature of the Florida Current are key parameters affecting the transport of heat into the North Atlantic, yet little is known about their variability on centennial time scales. Here we report replicated, high-resolution foraminiferal records of Florida Current surface hydrography for the last millennium from two coring sites, Dry Tortugas and the Great Bahama Bank. The oxygen isotopic composition of Florida Current surface water (δ18Ow) near Dry Tortugas increased 0.4‰ during the course of the Little Ice Age (LIA: ~1200-1850 A. D.), equivalent to a salinity increase of 0.8-1.5 psu. On the Great Bahama Bank, where surface waters are influenced by the North Atlantic subtropical gyre, δ18Ow increased by 0.3‰ during the last 200 years. Although a portion (~0.1‰) of this shift may be an artifact of anthropogenically-driven changes in surface water ΣCO2, the remaining δ18Ow signal implies a 0.4 to 1 psu increase in salinity after 200 yr BP. The simplest explanation of the δ18Ow data is southward migration of the Atlantic Hadley circulation during the LIA. Scaling of the δ18Ow records to salinity using the modern low-latitude δ18Ow-S slope produces an unrealistic reversal in the salinity gradient between the two sites. Only if δ18Ow is scaled to salinity using a high-latitude δ18Ow-S slope can the records be reconciled. Changes in atmospheric 14C paralleled shifts in Dry Tortugas δ18Ow, suggesting that variable solar irradiance paced centennialscale ITCZ migration and changes in Florida Current salinity during the last millennium.This work was supported by NSF grant OCE-0096469

    Experimental characterization of the effects of pneumatic tubing on unsteady pressure measurements

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    Advances in aircraft control system designs have, with increasing frequency, required that air data be used as flight control feedback. This condition requires that these data be measured with accuracy and high fidelity. Most air data information is provided by pneumatic pressure measuring sensors. Typically unsteady pressure data provided by pneumatic sensing systems are distorted at high frequencies. The distortion is a result of the pressure being transmitted to the pressure sensor through a length of connective tubing. The pressure is distorted by frictional damping and wave reflection. As a result, air data provided all-flush, pneumatically sensed air data systems may not meet the frequency response requirements necessary for flight control augmentation. Both lab and flight test were performed at NASA-Ames to investigate the effects of this high frequency distortion in remotely located pressure measurement systems. Good qualitative agreement between lab and flight data are demonstrated. Results from these tests are used to describe the effects of pneumatic distortion in terms of a simple parametric model

    Using Cesium 137 to Understand Recent in Cave Sedimentation in the Tongass National Forest, Southeast Alaska

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    Removal of vegetation and subsequent erosion in karst regions such as central Kentucky or southeastern Alaska often leads to increased sedimentation in karst features such as caves and dolines. This sedimentation can impact the ground water by altering flow paths and the bio-geochemistry of the karst aquifer itself. Various methodologies have been used to obtain quantitative erosion and sedimentation rates for surface areas in karst and non-karst settings, but few quantitative studies have taken place in caves. The purpose of this study is to examine the effects of timber harvesting and development upon the caves and karst of southeastern Alaska by determining the recent (post 1954) sediment accumulation rates. Cesium 137 from open-air nuclear testing was is used to determine the age of the sediments in caves, surface karst features and undisturbed areas. Sediments generated from surface land disturbances and deposited in caves and karst features since 1954 may have positive cesium activities, whereas sediments deposited in caves and karst features before 1954 (the beginning of 137Cs deposition in the environment) will have little or no cesium activity. The method was successfully tested in the main river passage of Big Bertha Cave in south-central Kentucky before fieldwork commenced in Alaska. Samples collected from sediment berms in the study areas were analyzed for 137Cs on the EG and G High Purity Germanium detector at the Western Kentucky University Applied Physics Institute for a period of 12 hours. Results from each site were obtained in terms of peak area (net counts) and then converted into international units (Bq/Kg). Vertical profiles of cesium activity were constructed for each site and a minimum sediment accumulation rate (in cm per year) calculated. This sedimentation rate represents a minimum rate of sediment accumulation since it does not take into account the removal and re deposition of sediment during flood events. The Alaskan caves and karst areas selected for this study are all within or downstream from areas of significant development and /or timber harvesting, and cesium 137 is present at all locations. Recent sedimentation rates in the sampled caves and karst of southeastern Alaska range from approximately 1.5 cm/year to over 6 cm/year, and it appears that recent timber harvesting has had a significant effect upon sedimentation in these areas

    Revealing Relationships among Relevant Climate Variables with Information Theory

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    A primary objective of the NASA Earth-Sun Exploration Technology Office is to understand the observed Earth climate variability, thus enabling the determination and prediction of the climate's response to both natural and human-induced forcing. We are currently developing a suite of computational tools that will allow researchers to calculate, from data, a variety of information-theoretic quantities such as mutual information, which can be used to identify relationships among climate variables, and transfer entropy, which indicates the possibility of causal interactions. Our tools estimate these quantities along with their associated error bars, the latter of which is critical for describing the degree of uncertainty in the estimates. This work is based upon optimal binning techniques that we have developed for piecewise-constant, histogram-style models of the underlying density functions. Two useful side benefits have already been discovered. The first allows a researcher to determine whether there exist sufficient data to estimate the underlying probability density. The second permits one to determine an acceptable degree of round-off when compressing data for efficient transfer and storage. We also demonstrate how mutual information and transfer entropy can be applied so as to allow researchers not only to identify relations among climate variables, but also to characterize and quantify their possible causal interactions.Comment: 14 pages, 5 figures, Proceedings of the Earth-Sun System Technology Conference (ESTC 2005), Adelphi, M

    Family System of Advanced Charring Ablators for Planetary Exploration Missions

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    Advanced Ablators Program Objectives: 1) Flight-ready(TRL-6) ablative heat shields for deep-space missions; 2) Diversity of selection from family-system approach; 3) Minimum weight systems with high reliability; 4) Optimized formulations and processing; 5) Fully characterized properties; and 6) Low-cost manufacturing. Definition and integration of candidate lightweight structures. Test and analysis database to support flight-vehicle engineering. Results from production scale-up studies and production-cost analyses

    Automated system to measure the carbonate concentration of sediments

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    We have developd a computer controlled system to measure the calcium carbonate content of sediment samples. A menu driven program controls the analysis of each sample. The system first communicates with a Mettler digital balance to record the weights of the 40 samples which must be loaded into each run. The sample boats are next loaded into the sample carousel which is then sealed from the atmosphere. The system is first pumped down to a vacuum of 0.04 torr. The valve to the pump closes and the stepping motor turns the carousel, moving a sample boat over the delivery slot and dropping the sample into 80°C 100% phosphoric acid under vigorous spinning action. During the reaction, carbonate is evolved into H2O and CO2 and the resulting pressure change within the closed system is measured by a pressure transducer and recorded into memory next to the sample identification and sample weight. The system is pumped once again to 0.04 torr and the process continues until all 40 samples have been analyzed. The data can then be uploaded and converted to percent carbonate values using a regression line produced from multiple analyses of varying weights of a 100% carbonate standard. Precision of the system, based upon 120 replicate analysis ranges from 0.49% to 0.88%.Funding was provided by the National Science Foundation through Grant Nos. OCE 85-11014 and OCE 88-13307

    Decreased influence of Antarctic intermediate water in the tropical Atlantic during North Atlantic cold events

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    © The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Earth and Planetary Science Letters 389 (2014): 200-208, doi:10.1016/j.epsl.2013.12.037.Antarctic Intermediate Water (AAIW) is a key player in the global ocean circulation, contributing to the upper limb of the Atlantic Meridional Overturning Circulation (AMOC), and influencing interhemispheric heat exchange and the distribution of salinity, nutrients and carbon. However, the deglacial history of AAIW flow into the North Atlantic is controversial. Here we present a multicore-top neodymium isotope calibration, which confirms the ability of unclean foraminifera to faithfully record bottom water neodymium isotopic composition (εNdεNd) values in their authigenic coatings. We then present the first foraminifera-based reconstruction of εNdεNd from three sediment cores retrieved from within modern AAIW, in the western tropical North Atlantic. Our records reveal similar glacial and interglacial contributions of AAIW, and a pronounced decrease in the AAIW fraction during North Atlantic deglacial cold episodes, Heinrich Stadial 1 (HS1) and Younger Dryas (YD). Our results suggest two separate phases of reduced fraction of AAIW in the tropical Atlantic during HS1, with a greater reduction during early HS1. If a reduction in AAIW fraction also reflects reduced AMOC strength, this finding may explain why, in many regions, there are two phases of hydrologic change within HS1, and why atmospheric CO2 rose more rapidly during early than late HS1. Our result suggesting less flow of AAIW into the Atlantic during North Atlantic cold events contrasts with evidence from the Pacific, where intermediate-depth εNdεNd records may indicate increased flow of AAIW into the Pacific during the these same events. Antiphased εNdεNd behavior between intermediate depths of the North Atlantic and Pacific implies that the flow of AAIW into Atlantic and Pacific seesawed during the last deglaciation.This work was supported by US NSF grants and a Lawrence J. Pratt and Melinda M. Hall Endowed Fund for Interdisciplinary Research Award to D.W.O. and W.B.C. and by a Taiwan NSC Postdoctoral Fellowship (NSC98-2917-I-564-132) to K.F.H
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