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  • 1
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    PANGAEA
    In:  Supplement to: Dickens, Gerald Roy; Kennedy, B Mack (2000): Noble gases in methane hydrate from the Blake Ridge. In: Paull, CK; Matsumoto, R; Wallace, PJ; Dillon, WP (eds.) Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 164, 1-6, https://doi.org/10.2973/odp.proc.sr.164.211.2000
    Publication Date: 2024-01-09
    Description: Fractionation of the noble gases should occur during formation of a Structure I gas hydrate from water and CH4 such that CH4 hydrate is greatly enriched in Xenon. Noble gas concentrations and fractionation factors (F[4He], F[22Ne], F[86Kr], and F[132Xe] as well as R/Ra) were determined for eight gas hydrate specimens collected on Leg 164 to evaluate this theoretical possibility and to assess whether sufficient quantities of Xe are hosted in oceanic CH4 hydrate to account for Xe "missing" from the atmosphere. The simplest explanation for our results is that samples contain mixtures of air and two end-member gases. One of the end-member gases is depleted in Ne, but significantly enriched in Kr and Xe, as anticipated if the source of this gas involves fractionation during Structure I gas hydrate formation. However, although oceanic CH4 hydrate may be greatly enriched in Xe, simple mass balance calculations indicate that oceanic CH4 hydrate probably represents only a minor reservoir of terrestrial Xe. Noble gas analyses may play an important role in understanding the dynamics of gas hydrate reservoirs, but significantly more work is needed than presented here.
    Keywords: 164-994C; 164-996B; 164-996C; 164-996E; 164-997A; Argon-36; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Elevation of event; Error, absolute; Event label; Fractionation factor; Fractionation factor, error; Joides Resolution; Latitude of event; Leg164; Longitude of event; Nicaraguan Rise, North Atlantic Ocean; Ocean Drilling Program; ODP; ORDINAL NUMBER; Ratio; Sample code/label; Sample ID; South Atlantic Ocean
    Type: Dataset
    Format: text/tab-separated-values, 104 data points
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  • 2
    Publication Date: 2020-01-08
    Description: In response to rapid decompression, porous magma may fragment explosively. This occurs when the melt can no longer withstand forces exerted upon it due to the overpressure in included bubbles. This occurs at a critical pressure difference between the bubbles and the surrounding magma. In this study we have investigated this pressure threshold necessary for the fragmentation of magma. Here we present the first comprehensive, high temperature experimental quantification of the fragmentation threshold of volcanic rocks varying widely in porosity, permeability, crystallinity, and chemical composition. We exposed samples to increasing pressure differentials in a high temperature shock tube apparatus until fragmentation was initiated. Experimentally, we define the fragmentation threshold as the minimum pressure differential that leads to complete fragmentation of the pressurized porous rock sample. Our results show that the fragmentation threshold is strongly dependent on porosity; high porosity samples fragment at lower pressure differentials than low porosity samples. The fragmentation threshold is inversely proportional to the porosity. Of the other factors, permeability likely affects the fragmentation threshold at high porosity values, whereas chemical composition, crystallinity and bubble size distribution appear to have minor effects. The relationship for fragmentation threshold presented here can be used to predict the minimum pressure differential necessary for the initiation or cessation of the explosive fragmentation of porous magma.
    Description: Published
    Description: 139-148
    Description: partially_open
    Keywords: fragmentation ; threshold ; experimental ; volcanology ; magma ; eruption ; porosity ; decompression ; 04. Solid Earth::04.08. Volcanology::04.08.02. Experimental volcanism
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Format: 411365 bytes
    Format: application/pdf
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  • 3
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A novel x-ray diffractometer was installed at the Australian National Beamline Facility at the Photon Factory, Japan, in October 1993. One of the major capabilities of the instrument is high speed high resolution powder diffraction using imaging plate detectors. The diffractometer combines a two circle goniometer and a large cassette in which imaging plates can be loaded covering 320° of 2θ. The diffractometer is enclosed in a large vacuum chamber and can be operated in air, vacuum, or helium. Recently, powder data has been obtained from rutile (TiO2) and NBS Si 640b at wavelengths from 0.62 to 1.9 A(ring) using imaging plates, and has been used to characterize the performance of the instrument. The data has been refined using the Rietveld method and R values of under 2% obtained. The resolution of the system varies from a minimum of about 0.04° to around 0.25° at 2θ angles around 160°, which is the equal of most synchrotron based powder diffractometers, and only slightly worse than that obtained using an analyzer crystal and scintillation detector. Using the imaging plates, 160° of data is simultaneously acquired in an exposure of about 10 min, compared to conventional counter diffractometer scans which routinely exceed 10 hours. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Inorganic chemistry 3 (1964), S. 265-268 
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 47 (1982), S. 0 
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The bioavailability of iron formed by the corrosion of low-carbon steel (99% Fe) in contact with Red Delicious apples was measured in a rat model using a depletion-repletion experiment. The percentage of ingested iron converted to hemoglobin iron (Conversion Efficiency) was 74, 57, and 56%, respectively, for daily doses of 110, 190, and 285 μg of this iron. (Conversion Efficiency for FeSO4 was 46-50%). When compared with FeSO4= 100, the relative biological value of this iron was found to range from 93–153. Ingestion of one Red Delicious apple that has been exposed to eight large iron nails for 24 hr could provide 10–15 mg iron having good bioavailability.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0196-9781
    Keywords: Catecholamine ; Chromaffin ; Chromogranin ; Chromostatin
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 95 (1973), S. 6907-6913 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food science 39 (1974), S. 0 
    ISSN: 1750-3841
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 78 (1989), S. 735-740 
    ISSN: 1432-2242
    Keywords: Individual loci ; Estimation ; Genetic counseling ; Genotype probabilities ; Accuracy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A Bayesian method to estimate genotype probabilities at a single locus using information on the individual and all its relatives and their mates has been developed. The method uses data over several generations, can deal with large numbers of individuals in large livestock families and allows for missing information. It can be extended to multiple alleles and can be used for autosomal or sex-linked loci. The allele frequencies and the form of expression (dominance, penetrance) must be specified. An algorithm using the method and involving an iterative procedure has been developed to calculate the genotype probabilities for practical use in livestock breeding. The method and algorithm were used to determine the accuracy of estimating genotype probabilities of sires for a female sex-limited trait, such as genetic variants of milk proteins. Data were similated and genotype probabilities estimated for 100 sires (20 replicates) with 3, 6 and 12 female offspring per sire, for different population frequencies, for additive and dominance gene action and for variable genotypic expression. Such simulation is useful in the design of testing systems for the use of information on specific genetic loci in selection.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 85 (1993), S. 706-712 
    ISSN: 1432-2242
    Keywords: Selection index ; Tandem selection ; Multiple selection ; Linkage disequilibrium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A theoretical comparison between two multiple-trait selection methods, index and tandem selection, after several generations of selection was carried out. An infinite number of loci determining the traits, directional and truncation selection, discrete generations and infinite population size were assumed. Under these assumptions, changes in genetic parameters over generations are due to linkage disequilibrium generated by selection. Changes continue for several generations until equilibrium is approached. Algebraic expressions for asymptotic responses from index selection can be derived if index weights are maintained constant across generations. Expressions at equilibrium for genetic parameters and responses are given for the index and its component traits. The loss in response by using initial index weights throughout all generations, instead of updating them to account for changes in genetic parameters, was analyzed. The benefit of using optimum weights was very small ranging from 0% to about 1.5% for all cases studied. Recurrence formulae to predict genetic parameters and responses at each generation of selection are given for both index and tandem selection. A comparison between expected response in the aggregate genotype at equilibrium from index and tandem selection is made considering two traits of economic importance. The results indicate that although index selection is more efficient for improving the aggregate breeding value, its relative efficiency with respect to tandem selection decreases after repeated cycles of selection. The reduction in relative efficiency is highest with the highest selection intensity and heritabilities and with negative correlations between the two traits. The advantage of index over tandem selection might be further reduced if changes in genetic parameters due to gene frequency changes produced by selection, random fluctuations due to the finite size of the population, and errors in estimation of parameters, were also considered.
    Type of Medium: Electronic Resource
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