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  • 1
    Electronic Resource
    Electronic Resource
    Nuclear diagnostics for the National Ignition Facility (invited) : Papers from the thirteenth topical conference on high temperature plasma diagnostics (2001)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 72 (2001), S. 773-779 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The National Ignition Facility (NIF), currently under construction at the Lawrence Livermore National Laboratory, will provide unprecedented opportunities for the use of nuclear diagnostics in inertial confinement fusion experiments. The completed facility will provide 2 MJ of laser energy for driving targets, compared to the approximately 40 kJ that was available on Nova and the approximately 30 kJ available on Omega. Ignited NIF targets are anticipated to produce up to 1019 DT neutrons. In addition to a basic set of nuclear diagnostics based on previous experience, these higher NIF yields are expected to allow innovative nuclear diagnostic techniques to be utilized, such as neutron imaging, recoil proton techniques, and gamma-ray-based reaction history measurements. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1319356
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  • 2
    Electronic Resource
    Electronic Resource
    Neutron time-of-flight and emission time diagnostics for the National Ignition Facility : Papers from the thirteenth topical conference on high temperature plasma diagnostics (2001)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 72 (2001), S. 850-853 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Current plans call for a system of current mode neutron detectors for the National Ignition Facility for extending the range of neutron yields below that of the neutron activation system, for ion-temperature measurements over a wide yield range, and for determining the average neutron emission time. The system will need to operate over a yield range of 106 for the lowest-yield experiments to 1019 for high-yield ignited targets. The requirements will be satisfied using several detectors located at different distances from the target. This article presents a conceptual design for the NIF nToF system. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1321001
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  • 3
    Electronic Resource
    Electronic Resource
    Electrical characterization of cw xenon arcs at moderate currents (1987)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 61 (1987), S. 4484-4491 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Radiant output, current-voltage characteristics, and heat conduction losses have been measured for water-cooled xenon arc lamps with d=0.7-cm quartz envelopes, driven by 60-Hz currents I ranging from 10 to 90-A rms. Cold-fill pressures varied from 0.5 to 3.0 atm absolute, and interelectrode spacing S from 11.0 to 20.3 cm. The arc voltage drop has been fitted to an equation of the form V=AIbpcaS/d with the results of A, b, and c being 2.51±0.20, 0.40±0.03, and 0.23±0.04, respectively. Here pa is an effective gas-fill pressure which depends on the ratio of hot-arc volume to cold-lamp volume and accounts for the lower atom density in the hot arc. The percentage of lamp power appearing as near-visible continuum radiation varies in the approximate range, 55%–65%. Our voltage data are compared to the high-current empirical Goncz result and with two simple theoretical models: a gray body ion-resistive arc and a recombination dominated atom-resistive arc. We estimate that the plasma has a very small emissivity. The analysis emphasizes the importance of recombination as a source of continuum radiation in these moderate current arcs and that both atoms and ions contribute to plasma resistivity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.338934
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  • 4
    Electronic Resource
    Electronic Resource
    Nitrogen metabolism and excretion in Allenbatrachus grunniens(L): effects of variable salinity, confinement, high pH and ammonia loading (2004)
    Oxford, UK; Malden, USA : Blackwell Science Ltd
    Journal of fish biology 65 (2004), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The nitrogen metabolism and excretion patterns of the grunting toadfish Allenbatrachus grunniens and the effects of salinity on these processes were examined. Individuals of A. grunniens were subjected to several experimental treatments, including variable salinity (2 to 30), high pH (8·5 compared to 7·0 for controls), high environmental ammonia (10 mM) and confinement to small water volumes, and measurements were made of activities of selected enzymes of nitrogen metabolism, ammonia and urea excretion rates, and tissue and plasma contents of ammonia, urea and amino acids. Activities of key ornithine-urea cycle enzymes were rather low (e.g. liver carbamoyl phosphate synthetase III activity was 0·001 μmols min−1 g−1), and A. grunniens consistently demonstrated a low capacity for urea excretion despite significant elevations of plasma and tissue ammonia contents by the high pH and high ammonia treatments. This species could thus be categorized as ammoniotelic. Total free amino acid contents in plasma and tissues were increased by the high pH and high ammonia treatments, but no patterns were discerned in individual amino acids that would indicate any preferential accumulation (e.g. alanine and glutamine) as has been noted previously in several semi-terrestrial fish species. Thus, it appeared that A. grunniens was not unusual in its patterns of nitrogen metabolism and excretion in comparison to other ‘typical’ teleosts. Furthermore, manipulation of salinity had no major effects on nitrogen excretion in either this species or in comparative studies with the ureotelic gulf toadfish Opsanus beta. The results are discussed in the context of the broader pattern of nitrogen metabolism and excretion in the Batrachoididae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.0022-1112.2004.00538.x
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  • 5
    Electronic Resource
    Electronic Resource
    Field studies on the ureogenic gulf toadfish in a subtropical bay. I. Patterns of abundance, size composition and growth (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 50 (1997), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Opsanus beta abundance in Biscayne Bay, Florida, varied significantly depending on site and season. O. beta catch per unit effort (cpue) was highest in southern study sites which tended to provide the combination of shallow mean depth, nocturnally high levels of dissolved oxygen, and Thalassia-dominated substrate. Significant seasonal differences in abundance were restricted to the three sites where O. beta cpue tended to be highest; two of these sites shared the same pattern of in crease during the cool-dry season (November-April), followed by a return to lower levels during warm-wet season (May-September). Dramatic seasonal abundance increases could not be ascribed to large influxes of immature fish. Rather, size composition data suggested sexually mature individuals moved seasonally among habitats, possibly for reproductive purposes. Modal analysis of length-frequency data followed by nonlinear regressions yielded preliminary values for the von Bertalanffy growth parameters K and t0, given that Lσ= 300 mm. Possible reasons for O. beta growing slower and attaining a smaller maximal size than its temperate congener, O. tau, are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1997.tb01651.x
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  • 6
    Electronic Resource
    Electronic Resource
    Variation in urea excretion in the gulf toadfishOpsanus beta (1990)
    Springer
    Marine biology 106 (1990), S. 323-328 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Under long-term (24 h) control measurements, significant urea was excreted (15 to 90% of excreted nitrogen) byOpsanus beta (Goode and Bean) collected in 1989 from Biscayne Bay, Florida, USA. Urea excretion rates and plasma urea concentrations were not affected by antibiotic treatments which decreased intestinal microbe populations. These results suggest that nitrogen recycling by gut microbe urease is probably not significant in this species. Urea excretion rates increased significantly following 8 h of air-exposure and in response to high levels of NH4Cl. These results suggest that urea is synthesized and excreted by the toadfish primarily in situations that limit ammonia excretion. Thus, the ornithineurea cycle in the toadfish liver primarily maintains low concentrations of ammonia within the fish. High levels of variability in urea excretion rates and variation in response to air-exposure suggest that urea synthetic rates are affected by immediate past environmental conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01344308
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  • 7
    Electronic Resource
    Electronic Resource
    Activities of metabolic enzymes in the deep-water crabsChaceon fenneri andC. quinquedens and the shallow-water crabCallinectes sapidus (1990)
    Springer
    Marine biology 106 (1990), S. 343-346 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The activities of 18 enzymes were measured in gill, hepatopancreas and muscle tissue of the deep-water crabsChaceon fenneri andC. quinquedens and the shallow-water crabCallinectes sapidus collected from the Gulf of Mexico in January 1989. The activities of catabolic enzymes were correlated in general with the known metabolic rates of the three species. Activities were much higher inC. sapidus than inChaceon fenneri andC. quinquedens. In some cases,C. quinquedens had higher activities thanC. fenneri. The activities of enzymes of amino acid metabolism (glutamate dehydrogenase and alanine aminotransferase) were higher inC. quinquedens, which had high hemolymph [ammonia] and ammonia excretion rates. The activity of lactate dehydrogenase (LDH) ofC. fenneri andC. quinquedens were correlated with the two species' abilities to withstand hypoxia. The more hypoxiatolerant species,C. quinquedens, had higher activity of LDH in its muscles than didC. fenneri.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01344310
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  • 8
    Electronic Resource
    Electronic Resource
    Temperature adaptation in sea anemones: Physiological and biochemical variability in geographically separate populations of Metridium senile (1981)
    Springer
    Marine biology 62 (1981), S. 25-34 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Latitudinally separate populations of the sea anemone Metridium senile (L.) are very similar genetically by electrophoretic criteria, yet respond differently to temperature. Anemones from southern and northern California (USA) have different oxygen consumption patterns in response to acclimatory and acute changes in temperature. Northern anemones show a pronounced increase in Q10 at temperatures just above the normal environmental range, but southern anemones do not. The two populations also differed in the extent of metabolic compensation to temperature following several weeks of acclimation. This acclimation regime resulted in changes in the activities of several enzymes of intermediary metabolism, yet the extent and direction of these changes did not display a consistent trend with regard to acclimation temperature or population. The biochemical concomitants of acclimatory and acute temperature effects were studied further by measuring the concentrations of adenylates (ATP, ADP, and AMP) in anemones from the two populations exposed to different temperature regimes. During cold acclimation for several weeks, total adenylate concentrations (AT) increased in both the southern and northern populations, possibly due to metabolic rate compensation, since AT is positively correlated with tissue metabolic rate in many species. Moreover, the extremely low weight-specific oxygen consumption rates of M. senile are probably related to its very low AT values. Acute temperature decreases had no effect on adenylate concentrations and adenylate energy charge (AEC); in contrast, acute temperature increases led to large changes in adenylate concentrations. The effects of starvation on adenylate concentrations are pronounced, and the effect is temperature-dependent. In starved individuals held at 20°C, AEC values fell to 50% of normal values after 8 d, while those held at 10°C maintained normal AEC values.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00396948
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  • 9
    Electronic Resource
    Electronic Resource
    Sub-lethal plant defences: the paradox remains (1993)
    Springer
    Oecologia 93 (1993), S. 153-155 
    Details
    ISSN: 1432-1939
    Keywords: Panolis flammea ; Natural enemies ; Host quality ; Larval development ; Pinus contorta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lodgepole pine (Pinus contorta) trees of two different seed origins, one a poor quality host (Alaskan lodgepole pine), the other a good quality host (south coastal lodgepole pine), were infested with known numbers of eggs of the pine beauty moth, Panolis flammea. Each tree had paired sleeves, one allowing access by invertebrate predators, the other denying this access. When the sleeves were removed, the numbers of larvae surviving, their weights and developmental stages were assessed. Larvae reared on south coastal lodgepole pine (SLP) in the absence of predators were significantly heavier and had significantly better survival rates than larvae reared in comparable conditions on Alaskan lodgepole pine (ALP). However, in the open sleeves, although the larvae reared on SLP were significantly heavier than those on ALP, survival was significantly greater on ALP. Thus predation was greater on the faster developing larvae on the better quality host. These results indicate that slow growth by a herbivore does not necessarily result in greater vulnerability to predators.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00317663
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  • 10
    Electronic Resource
    Electronic Resource
    Metabolic scaling, buoyancy, and growth in larval Atlantic menhaden, Brevoortia tyrannus (1992)
    Springer
    Marine biology 112 (1992), S. 17-22 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We measured growth of larval Atlantic menhaden, Brevoortia tyrannus in terms of mass, volume, and weight in water as well as the mass-specific activities of the metabolic enzymes citrate synthase, lactate dehydrogenase, and malate dehydrogenase. Weight in water, the force the fish must exert to maintain vertical position, increases by a factor of 18 in larvae growing from 10 to 15 mm. The weight increase coincides with the development of the larval swim bladder. The activities of all three enzymes per unit mass of fish tissue decline greatly over this time period, indicating that the fish does not further develop its aerobic and anaerobic metabolic capacity for swimming during this growth interval.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349722
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