Search

Abstract Exploration and production in the deepwater Gulf of Mexicois hampered by an absence of existing survey data. In the late 1980s and early 1990s, NOAA ventured to map the deep Gulf of Mexico with multibeam sonar. Unfortunately, this visionary project lacked both the funding for completion and the technology to provide the survey accuracy and resolution presently desired. An aggressive campaign has been initiated to acquire and evaluate collocated multibeam bathymetry, acoustic reflectivity, gravity, magnetic, and sub-bottom data across 17,000 square miles of the uncharted deepwater Gulf of Mexico. Evaluation of these data is being accomplished with new technology developed by the University of New Brunswick, Canada, which interactively integrates them into one common graphical environment. "Fly-throughs" of geo-referenced data provide construction planning, production analysis, and allow for the establishment of geologic correlation. Interrelationships associated with the collection, processing, and interpretation of these various data sets and the benefit of multibeam bathymetry on the 3D Bouguer correction are discussed. NOAA Surveys The National Oceanographic and Atmospheric Administration (NOAA) was forerunner in the application of multibeam technology in the Gulf of Mexico. From 1989 to 1992, NOAA conducted a successful campaign of mapping the Gulf beyond the continental shelf. A lack of governmental funding brought the program to a halt prior to its completion. Consequently, a large "data gap" exists in the areas of East Breaks, Alaminos Canyon, and the western half of Garden Banks (Fig. 1). The NOAA program involved the incorporation of two different multibeam bathymetry systems that were state-of-the-art at the time. For waters shallower than 1000 meters, the Hydrochart II was employed. This system operated at 36 kHz and provided 17 beams across a swath of 2.5 times the water depth. A 12 kHz Sea Beam system was employed for waters deeper than 1000 meters. It provided an array of 16 beams across a swath of 0.7 times the water depth. The sounding density that resulted varies as a function of the water depth, vessel speed, and the system used, but a 250-meter bin is the most common filter applied to these data (across-track raw sounding densities range from approximately 75 meters to 130 meters). The 250-meter filter provides multiple soundings per bin, allowing statistical leverage for an accurate sounding selection. Similar calibration methods were employed for the Hydrochart II and the 12 kHz Sea Beam systems. These comprised of iterations that included:Collecting sounding data on predefined survey lines.Comparing charted, overlaid contours of sounding data.Scaling offsets from charts.Entering offset values into LOTUS-123 spreadsheets for evaluation.1,2 Considering the technical limitations of the positioning systems, motion sensors, processing systems, and multibeam systems employed at the time, this method of calibration served its purpose quite well (some organizations still employ this method in cases of shallow waters and narrow swaths).

A Space Shuttle Main Engine (SSME) test program was conducted between August 1995 and May 1996 using the Technology Test Bed (TTB) Engine. SSTO vehicle studies have indicated that increases in the propulsion system operating range can save significant weight and cost at the vehicle level. This test program demonstrated the ability of the SSME to accommodate a wide variation in safe operating ranges and therefore its applicability to the SSTO mission. A total of eight tests were completed with four at Marshall Space Flight Center's Advanced Engine Test Facility and four at the Stennis Space Center (SSC) A-2 attitude test stand. Key demonstration objectives were: 1) Mainstage operation at 5.4 to 6.9 mixture ratio; 2) Nominal engine start with significantly reduced engine inlet pressures of 50 psia LOX and 38 psia fuel; and 3) Low power level operation at 17%, 22%, 27%, 40%, 45%, and 50% of Rated Power Level. Use of the highly instrumented TTB engine for this test series has afforded the opportunity to study in great detail engine system operation not possible with a standard SSME and has significantly contributed to a greater understanding of the capabilities of the SSME and liquid rocket engines in general.

Currently, most antenna array designs are mechanically steered. However, as demand for higher performance antennas increases, an electronic replacement for the mechanical system becomes necessary. An alternative that may prove to be more cost effective is to use ferrite patch antennas as the elements in the array. The antenna's radiation characteristics are controlled by the direction and magnitude of the imposed magnetic fields that bias the ferrite. This is accomplished without requiring additional circuitry in the signal path. An initial study of this type of device was performed. The advanced ferrite handling capability of Ansoft HFSS was used to simulate the radiation characteristics of ferrite patch antennas. The simulation capability of this finite element field simulation tool with its advanced absorbing boundary condition to simulate ferrite patch antennas was studied. The advantage of this type of solver is the ability to analyze ferrites with non-uniform bias fields. Through this investigation a better understanding of the operating characteristics of ferrite patch antennas was achieved.

The goal of the Virtual Prototyping Environment (VPE) is to decrease product development time and costs and to increase quality and flexibility by providing continuous computer support for the development cycle. Virtual prototype are directly derived from integrated CAD- Systems and enriched with simulation data. In addition, the VPE supports cooperative teams by providing different Computer Supported Cooperative Work (CSCW) techniques of shared viewing environments in combination with further communication tools for long distance collaboration. One aspect of CSCW in VPE's is multi-user and multi-application Shared 3D Environments. In the shared environment model, 3D objects from different applications can be joined into one scene that can be viewed by different users with independent or shared camera positions, enabling the distribution of visualization tasks between smaller, flexible and more specialized applications. The underlying product model of the VPE is based on the STEP standard applied to a distributed object-oriented data management approach. Taking the requirements from CE and shared 3D environments into account, we enriched the application interface to the data management with high level concepts such as object versioning, migration and consistency management, and extended the product data model to include presentation and annotation aspects.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Advance and retreat of temperate glaciers is largely controlled by changes in temperature and precipitation, but the relative importance of these drivers is debated. Numerical modeling of a New Zealand glacier reveals that temperature is the dominant control on glacier length. We find that a glacial advance, dated to ca. 13,000 yr B.P., requires a cooling event of 3–4 °C. This mid-latitude Southern Hemisphere cooling is similar in magnitude to the Antarctic Cold Reversal in the Vostok ice core record and likely to be a response to the same climate signal.

Des-tyrosine-gamma-endorphin (DT gamma E) has been reported to alleviate symptoms of schizophrenia. Attempting to replicate those reports, we administered 1 mg of DT gamma E, i.m., for 8 consecutive days to nine patients meeting the DSM-III criteria for schizophrenia. Patients in this double-blind, crossover, and placebo-controlled study showed a statistically significant, but clinically modest improvement. The improvement was detectable during the first several days of the DT gamma E treatment; the symptoms then returned to baseline level in spite of continued doses of DT gamma E. Testing the metabolism of DT gamma E in the patients' plasma, we found a high rate of formation and of degradation, but the metabolic rates were not related to clinical symptoms.

The subjects were 13 psychiatric inpatients with tardive dyskinesia. Each subject participated in two sessions. Either naloxone (10 mg) or placebo was administered intravenously during each session. In a subset of subjects (n = 7), blood samples for β-endorphin were drawn before and at 30 and 60 minutes after the injection. The Abnormal Involuntary Movement Scale was administered before and at 10, 20, 40, 60, 120, and 360 minutes after the injection. Double-blind procedures were maintained throughout the experiment. Neither naloxone nor placebo had any appreciable effect on the involuntary movements. Naloxone elicited a significant increase in the plasma β-endorphin.

Platelet aggregation in the Chandler tube was studied by continuous measurement of optical density during aggregation. Normal mean values for the duration of aggregation varied from 3.4 to 6.0 min. [rabbit platelet-rich plasma (PRP)] and 3.1 to 5.8 min. (human PRP). Mean thrombus formation time (TFT) varied from 17.1 to 20.9 min. (rabbit PRP) and from 13.5 to 16.4 min. (human PRP). Activation of Hageman factor shortened TFT and duration of aggregation, and minimized optical density changes during aggregation. Factor VIII and erythrocytes increased optical density changes during aggregation. The observations suggest that experimental and clinical states associated with an increased tendency to thrombosis may correlate with characteristic changes in optical density during aggregation in the Chandler system. Altered aggregation characteristics result from changes in plasma proteins, adenosine diphosphate release, catecholamine concentration, and the blood coagulation system.

SummaryThis case report describes a melanin-containing neurofibroma involving a spinal nerve root. Electron microscopy of the tumor shows that neoplastic Schwann cells are capable of melanogene-sis. Although this capability is suggested in the literature, few reports provide ultra-structural confirmation.The likely identity between reported “cellular blue nevi of spinal nerve roots” and nerve sheath tumors is discussed. It is possible that pigmented nerve sheath tumors behave more aggressively than nonpigmented ones, although it is debatable.

Ice-penetrating radar and modelling data are presented suggesting the presence of a zone of temperate ice, water ponding or saturated sediment beneath the tongue of Taylor Glacier, Dry Valleys, Antarctica. The proposed subglacial zone lies 3–6 km up-glacier of the terminus and is 400– 1000m across. The zone coincides with an extensive topographic overdeepening to 80m below sea level. High values of residual bed reflective power across this zone compared to other regions and the margins of the glacier require a high dielectric contrast between the ice and the bed and are strongly indicative of the presence of basal water or saturated sediment. Analysis of the hydraulic equipotential surface also indicates strong convergence into this zone of subglacial water flow paths. However, thermodynamic modelling reveals that basal temperatures in this region could not exceed –7˚C relative to the pressure-melting point. Such a result is at odds with the radar observations unless the subglacial water is a hypersaline brine.

International audience

Local wind speed variations influence the energy and mass fluxes over snow through snow accumulation, sublimation of drifting and blowing snow, or variations in turbulent fluxes over static snow and ice surfaces. We use idealized model experiments to analyze the sensitivity of turbulent fluxes over static snow surfaces to variations in wind speed under different climatic conditions. We find that the sensitivity (change in the turbulent flux per change of unit wind speed) increases with increasing air temperature and relative humidity. The sensitivity of turbulent fluxes to wind speed is highest when the stability parameter ζ = 1, which occurs at wind speeds typical for glacierized catchments (3-5 m s -1), and exponentially decreases either side of that range. That peak in sensitivity is caused by atmospheric stability corrections in the model, and occurs independently of the flux-profile relationships we tested. Our results quantify the significant effect of local wind speed variations on turbulent fluxes over snow and ice and can be used to estimate potential model uncertainties in different climates, especially for the typical assumption in distributed hydrological models that the wind speed is spatially constant. © 2012 Elsevier Ltd. All rights reserved.

Increasing attention is being paid to the application of uncertainty and sensitivity analysis methods to model validation and thermal systems simulation. The idea is to let users to apply uncertainty bands to their model input data. These bands are then propagated through the model to determine the uncertainty bands of the simulation results. One of the main difficulties the practitioner finds when trying to apply these techniques is the lack of information on the uncertainty that affects to typical input variables. This paper is a contribution to fill this gap. It quantifies the uncertainty that can be expected in the thermal conductivity of insulation materials in the lack of specific experimental measurements. Results are presented for specific materials and for groups of materials, in order to consider situations in which the material under consideration is not well defined. The proposed conductivities are derived from a large set of measurements that was compiled in a previous European project headed by the BRE Scottish Laboratory. To illustrate how the uncertainty bands can be used in practice, an example is discussed on the validation of the mathematical model of a solar thermal collector.

Publication in the conference proceedings of EUSIPCO, Aalborg, Denmark, 2010

To the Editor.— Although the FTAABS test is considered to be sensitive and specific for the diagnosis of syphilis, it may be falsely positive in several disease states, including systemic lupus erythematosus (SLE). The occurrence of a false-positive FTA-ABS in drug-induced lupus has previously been reported to occur only with procainamide. 1 We wish to report a case of hydralazine-induced lupus in which the FTA-ABS was falsely positive. A 68-year-old hypertensive woman had taken hydralazine hydrochloride, 50 mg four times daily, for two years. She gave a four-week history of fever, weight loss, severe muscle weakness, skin rash, arthralgias, and pleuritic chest pain. The fluorescent antinuclear antibody (FANA) test was positive at a titer of 1:1,280, homogeneous pattern, with negative determination for anti-DNA. The C 3 , C 4 , and total hemolytic complement levels were normal. Rheumatoid factor was negative. Creatine phosphokinase and aldolase levels were normal. A muscle biopsy specimen