436 research outputs found

    Description and evaluation of the Acoustic Profiling of Ocean Currents (APOC) system used on R. V. Oceanus cruise 96 on 11-22 May 1981

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    The underway current profiling system which consists of a microprocessor controlled data logger that collects and formats data from a four beam Ametek-Straza 300 kHz acoustic Doppler current profiler, heading from the ship's gyrocompass, and navigation information from a Loran-C receiver and a satellite navigation unit is discussed. Data are recorded on magnetic tape and real time is calculated. Time averaging is required to remove effects of ship motion. An intercomparison is made with a moored vector measuring current meter (VMCM). The mean difference in hourly averaged APOC and VMCM currents over the four hour intercomparison is a few mm s minus including: two Gulf Stream crossings, a warm core ring survey, and shallow water in a frontal zone to the east of Nantucket Shoals

    Introduction to Special Section: SAZ Project

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    Oceanographic processes in the subantarctic region contribute crucially to the phys. and biogeochemical aspects of the global climate system. To explore and quantify these contributions, the Antarctic Cooperative Research Center organized the SAZ Project, a multidisciplinary, multiship study carried out south of Australia in the austral summer of 1997-1998. We present an overview of the SAZ Project and some of its major results

    Metabolism and distribution of p,p'-DDT during flight of the white-crowned sparrow, Zonotrichia leucophrys

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    This study evaluated the interactions of flight, fasting, and 1,1,1-trichloro-bis(4-chlorophenyl)ethane (p,p′-DDT) loading on residue metabolism and distribution in recently exposed white-crowned sparrows (Zonotrichia leucophrys). Female sparrows were dosed with 5 mg p,p′-DDT per kg body weight over 3 d. Following 1 d of recovery, sparrows were flown in a wind tunnel for up to 140 min, in 15-min blocks. Food was withheld from the start of the flight period until birds were euthanized. DDT, 1,1-dichloro-2,2-bis(4 chlorophenyl)ethane (DDD), and 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (DDE) were present in all tissues examined. 1-Chloro-2,2-bis(4-chlorophenyl)ethene (DDµ), 1,1-bis(4-chlorophenyl)ethane (p,p′-DDη), and 2,2-bis(4-chlorophenyl)ethanol (p,p′-DDOH) were not found. Fasting did not significantly affect the rate of residue increase over time in any of the tissues examined. When sparrows flew and fasted simultaneously, fasting seldom contributed to an increase in tissue residues. However, the length of time flown was significantly correlated with increasing toxicant concentrations in the brain, kidney, and liver, effectively demonstrating the potential for brief flights to enhance mobilization of DDT and its metabolites. Dose, flight, and fasting also increased residues in brain tissue. These contaminant redistributions may have important ramifications on the stresses experienced by migratory birds

    Sustainable Grazing on Saline Land in Western Australia - Multidisciplinary Research Linking Producers and Scientists

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    Dryland salinity is one of the most critical environmental issues challenging Western Australian farmers. Currently 10% of the cropping zone (1.8 million ha) is salt-affected and this is predicted to increase dramatically in the next 50 years (NLWRA, 2001). Animals grazing saline pasture systems represent the most likely large-scale opportunity for economic return from saline land in the short to medium term. To date, few farmers have invested in large-scale revegetation of saline land as the economic return from grazing has not been perceived to cover costs. Furthermore other benefits of saltland pasture systems, such as biodiversity, water use and improved quality of animal products have not been quantified

    Five-Year Survival After Endosonography vs Mediastinoscopy for Mediastinal Nodal Staging of Lung Cancer.

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    Lung cancer accounts for the highest cancer-related mortality rate worldwide.1 Accurate mediastinal nodal staging is crucial in the management of non–small cell lung cancer (NSCLC) because it directs therapy and has prognostic value.2,

    How should performance in EBUS mediastinal staging in lung cancer be measured?

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    There has been a paradigm shift in mediastinal staging algorithms in non-small cell lung cancer over the last decade in the United Kingdom (UK). This has seen endoscopic nodal staging (predominantly endobronchial ultrasound, EBUS) almost replace surgical staging (predominantly mediastinoscopy) as the pathological staging procedure of first choic

    The neodymium isotope fingerprint of Adélie coast bottom water

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    Adélie Land Bottom Water (ALBW), a variety of Antarctic Bottom Water formed off the Adélie Land coast of East Antarctica, ventilates the abyssal layers of the Australian sector of the Southern Ocean as well as the eastern Indian and Pacific Oceans. We present the first dissolved neodymium (Nd) isotope and concentration measurements for ALBW. The summertime signature of ALBW is characterized by εNd = −8.9, distinct from Ross Sea Bottom Water, and similar to Weddell Sea Bottom Water. Adélie Land Shelf Water, the precursor water mass for wintertime ALBW, features the least radiogenic Nd fingerprint observed around Antarctica to date (εNd = −9.9). Local geology around Antarctica is important in setting the chemical signature of individual varieties of Antarctic Bottom Water, evident from the shelf water signature, which should be considered in the absence of direct wintertime observations

    Preparation of ibuprofen microparticles by antisolvent precipitation crystallization technique: characterization, formulation, and in vitro performance

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    This study demonstrates the preparation and characterization of ibuprofen (IBP) microparticles with some excipients by a controlled crystallization technique with improved dissolution performance. Using the optimum concentrations pluronic F127, hydroxypropyl methyl cellulose, D-mannitol, and L-leucine in aqueous ethanol, the IBP microparticles were prepared. The dissolution tests were performed in phosphate buffer saline using a United States Pharmacopoeia dissolution tester at 37°C. The Raman spectroscopy was used to investigate the interactions and distribution of the IBP with the additives in the microcrystals. The prepared IBP microparticles showed higher dissolution compared to that of the smaller sized original IBP particles. The Raman data revealed that the excipients with a large number of hydroxyl groups distributed around the IBP particle in the crystal enhanced the dissolution of the drug by increasing the drug-solvent interaction presumably through hydrogen bonding. The Raman mapping technique gave an insight into the enhanced dissolution behavior of the prepared IBP microparticles, and such information will be useful for developing pharmaceutical formulations of hydrophobic drugs. The controlled crystallization was a useful technique to prepare complex crystals of IBP microparticles along with other additives to achieve the enhanced dissolution profile

    Random Geometric Graphs

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    We analyse graphs in which each vertex is assigned random coordinates in a geometric space of arbitrary dimensionality and only edges between adjacent points are present. The critical connectivity is found numerically by examining the size of the largest cluster. We derive an analytical expression for the cluster coefficient which shows that the graphs are distinctly different from standard random graphs, even for infinite dimensionality. Insights relevant for graph bi-partitioning are included.Comment: 16 pages, 10 figures. Minor changes. Added reference
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