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  • 1
    Electronic Resource
    Electronic Resource
    1 nm x-ray lithography using novel mask fabrication technique (1998)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 69 (1998), S. 3350-3352 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: High-resolution commercial photomasks and x-ray masks are at present manufactured by a multistep process which involves the use of etching. This route imposes a limitation on the resolution that can be achieved. We describe here a new approach to the fabrication of x-ray masks involving the use of organometallic compounds which undergo direct conversion to metal under the influence of electron beam irradiation. This approach permits fabrication of both x-ray masks and extreme ultraviolet masks in essentially a single processing step. The attainable resolution is unaffected by any limitation incurred by etching processes and is dependent only on such factors as electron scattering and electron beam diameter. We describe here the production of a gold x-ray mask, which was used in conjunction with a compact laser plasma source to demonstrate the lithographic process. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1149099
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  • 2
    Electronic Resource
    Electronic Resource
    Early transition metal clusters with π-donor ligands edited by M. H. Chisholm (1997)
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 53 (1997), S. 323-323 
    Details
    ISSN: 1600-5740
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0108768197099692
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  • 3
    Electronic Resource
    Electronic Resource
    Effects of altering brain cholinergic activity on covert orienting of attention: comparison of monkey and human performance (1997)
    Springer
    Psychopharmacology 132 (1997), S. 324-334 
    Details
    ISSN: 1432-2072
    Keywords: Key words Attention ; Covert orienting ; Alerting ; Nicotine ; Atropine ; Reaction times ; Monkey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Experiments were conducted to elucidate the role of the cholinergic neurotransmitter system in arousal and the orienting of attention to peripheral targets. Rhesus monkeys and humans fixated a visual stimulus and responded to the onset of visual targets presented randomly in two visual field locations. The target was preceded by a valid cue (cue and target at the same location), an invalid cue (cue and target to opposite locations), a double cue (cues to both spatial locations, target to one), or, the cue was omitted (no-cue, target to either location). Reaction times (RTs) to the onset of the target were recorded. For monkeys, systemic injections of nicotine (0.003–0.012 mg/kg) or atropine (0.001–0.01 mg/kg), but not saline control injections, reduced mean RTs for all trials, indicating general behavioral stimulation. In addition, nicotine significantly reduced RTs for invalid trials but had little additional effect on those for valid, double, or no-cue trials. Virtually identical effects were observed for human chronic tobacco smokers in performing the same task following cigarette smoking. Injections of atropine in monkeys had no effect on RTs for valid or invalid trials but significantly slowed RTs in double-cue trials that did not require the orienting of attention. These results suggest that in both species, the nicotinic cholinergic system may play a role in automatic sensory orienting. In addition, the muscarinic system may play a role in alerting to visual stimuli in monkeys.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002130050352
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  • 4
    Electronic Resource
    Electronic Resource
    Scopolamine slows the orienting of attention in primates to cued visual targets (1999)
    Springer
    Psychopharmacology 142 (1999), S. 1-8 
    Details
    ISSN: 1432-2072
    Keywords: Key words Scopolamine ; Covert orienting ; Attention ; Monkey ; Reaction time ; Working memory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The cholinergic agonist nicotine facilitates visuospatial attention shifting, but the role of muscarinic cholinergic drugs in this behavior is unclear. In order to establish the generality of cholinergic action in attention shifting, we administered the muscarinic antagonist scopolamine to two rhesus monkeys trained to perform a cued target detection (Posner) task. In this task, monkeys signaled the detection of a peripheral visual target by releasing a switch and their reaction times were measured. The location of the target’s appearance was preceded by a cue that was either valid (target and cue in the same spatial location), invalid (target and cue to opposite hemifields), spatially uninformative (cues in both hemifields, target to one hemifield), or omitted altogether. Scopolamine produced a dose-dependent increase in all reaction times and a decrease in accuracy. The slowing was most prominent for valid cues in either visual field. However, slowing did not occur in trials whose cues lacked spatial information, or in tasks in which attention was directed to events at the fixation point, whether or not peripheral distractors were present. These results provide additional support for the hypothesis that acetylcholine plays a key role in reflexive attention shifting to peripheral visual targets.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002130050855
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  • 5
    Electronic Resource
    Electronic Resource
    Analysis of gut contents of Gomphiocephalus hodgsoni Carpenter (Collembola: Hypogastruridae) at Cape Geology, Antarctica (1996)
    Springer
    Polar biology 16 (1996), S. 463-467 
    Details
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The diet of the collembolan Gomphiocephalus hodgsoni was investigated by microscopic examination of the contents of 197 faecal pellets and 32 guts collected at Cape Geology, Victoria Land, Antarctica. Animals came from nine contrasting microhabitats, ranging from mineral soils to bryophyte cushions. Thirty-two different types of ingested material were recognised. Detritus, filamentous cyanobacteria, eukaryotic microalgae and fungal hyphae were the most frequent. There were marked contrasts between individuals collected from different microhabitats, which probably reflected food availability. There was some selectivity in that neither living moss tissue nor the macroscopic chlorophyte alga Prasiola crispa was encountered in faeces or guts, despite their being abundant in some microhabitats. A comparison of active and inactive animals showed the latter to have a significantly higher proportion of empty guts and of guts containing fat globules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003000050076
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  • 6
    Electronic Resource
    Electronic Resource
    Analysis of gut contents ofGomphiocephalus hodgsoni carpenter (collembola: Hypogastruridae) at Cape Geology, Antarctica (1996)
    Springer
    Polar biology 16 (1996), S. 463-467 
    Details
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The diet of the collembolanGomphiocephalus hodgsoni was investigated by microscopic examination of the contents of 197 faecal pellets and 32 guts collected at Cape Geology, Victoria Land, Antarctica. Animals came from nine contrasting microhabitats, ranging from mineral soils to bryophyte cushions. Thirty-two different types of ingested material were recognised. Detritus, filamentous cyanobacteria, eukaryotic microalgae and fungal hyphae were the most frequent. There were marked contrasts between individuals collected from different microhabitats, which probably reflected food availability. There was some selectivity in that neither living moss tissue nor the macroscopic chlorophyte algaPrasiola crispa was encountered in faeces or guts, despite their being abundant in some microhabitats. A comparison of active and inactive animals showed the latter to have a significantly higher proportion of empty guts and of guts containing fat globules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02329064
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  • 7
    Electronic Resource
    Electronic Resource
    Evidence-Based Diagnosis of Lyme Disease (1999)
    Springer
    European journal of clinical microbiology & infectious diseases 18 (1999), S. 484-489 
    Details
    ISSN: 1435-4373
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The aim of this study was to make an evidence-based comparison of four commercial enzyme immunoassays (EIAs) (Serion Classics, Sigma Diagnostics, Cambridge Biotech and ICN Diagnostics) and an in-house enzyme immunoassay (EIA) in order to select the most appropriate screening assay for diagnosis of Lyme disease. Borrelia burgdorferi sensu stricto cultured in BSK-H medium was used to develop the in-house assay. Escherichia coli antigen (0.9 mg/ml) was included in the serum diluent to reduce non-specific background. Comparison of the number of tests needed to diagnose (i.e. to indicate a positive result) and the cost per positive diagnosis for the five assays was made using a panel of 176 Western blot-characterised sera. The Cambridge Biotech and Sigma assays had the highest sensitivity but poorer specificity, whereas the Serion and ICN assays had highest specificity but poorer sensitivity. The in-house assay had average sensitivity and specificity, the number of tests needed to diagnose being 2.32 compared to 1.92 for Serion, 2.17 for ICN, 2.5 for Sigma and 2.7 for Cambridge Biotech. In a diagnostic protocol that uses an EIA as screening test, with confirmation by Western blot, a good balance of sensitivity and specificity is essential. The in-house assay was the most cost-effective (lowest cost per positive diagnosis), and is probably the best option for specialist laboratories in Europe.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100960050328
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  • 8
    Electronic Resource
    Electronic Resource
    Stability of the extreme point set of a polyhedron (1996)
    Springer
    Journal of optimization theory and applications 90 (1996), S. 357-380 
    Details
    ISSN: 1573-2878
    Keywords: Polyhedral sets ; extreme points ; multivalued maps ; continuity ; stability ; linear programming
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract This paper is focused on the stability properties of the extreme point set of a polyhedron. We consider a polyhedral setX(A,b) which is defined by a linear system of equality and inequality constraintsAx≤b, where the matrixA and the right-hand sideb are subject to perturbations. The extreme point setE(X(A,b)) of the polyhedronX(A,b) defines a multivalued map ℳ:(A,b)→E(X(A,b)). In the paper, characterization of continuity and Lipschitz continuity of the map ℳ is obtained. Boundedness of the setX(A,b) is not assumed It is shown that lower Lipschitz continuity is equivalent to the lower semicontinuity of the map ℳ and to the Robinson and Mangasarian-Fromovitz constraint qualifications. Upper Lipschitz continuity is proved to be equivalent to the upper semicontinuity of the map ℳ. It appears that the upper semicontinuity of the map ℳ implies the lower semicontinuity of this map. Some examples of using the conditions obtained are provided.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02190003
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