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  • 1
    Electronic Resource
    Electronic Resource
    Development of Leptographium wageneri on root surfaces and other substrata (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Forest pathology 27 (1997), S. 0 
    Details
    ISSN: 1439-0329
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Conidia of Leptographium wageneri var. ponderosum, Leptographium wageneri var. pseudotsugae and Leptographium wageneri var. wageneri germinated on wounded roots of ponderosa pine (Pinus ponderosa), Douglas fir (Pseudotsuga menziesii), and pinyon (Pinus edulis), but not on unwounded roots. On wounds, germination occurred regardless of the combination of pathogen variety and plant species. When wounded roots of ponderosa pine and Douglas fir seedlings were inoculated with conidia of L. w. var. ponderosum and L. w. var. pseudotsugae, respectively, 87-100% of the seedlings became infected. When unwounded roots were inoculated with wooden blocks colonized with L. wageneri, 60-66% of the seedlings became infected.The development of L. w. var. ponderosum and L. w. var. pseudotsugae on agar was compared with their development on agar overlaid with either cellophane or Nucleopore membranes. Undulating hyphae were found commonly in and on the agar, but less frequently on the membranes. On both membranes, mycelia formed mats which were tightly appressed to the surface; mats were not formed on the agar. On both agar and the membranes, two or more hyphae often formed a strand. When L. w. var. ponderosum mycelia were allowed to colonize the surface of an unwounded pine root, strands, undulating hyphae and poorly formed mats were seen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1439-0329.1997.tb01453.x
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  • 2
    Electronic Resource
    Electronic Resource
    On-Line and Off-Line Approximation Algorithms for Vector Covering Problems (1998)
    Springer
    Algorithmica 21 (1998), S. 104-118 
    Details
    ISSN: 1432-0541
    Keywords: Key words. Approximation algorithm, Worst case ratio, Competitive analysis, On-line algorithm, Packing problem, Covering problem.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract. This paper deals with vector covering problems in d -dimensional space. The input to a vector covering problem consists of a set X of d -dimensional vectors in [0,1] d . The goal is to partition X into a maximum number of parts, subject to the constraint that in every part the sum of all vectors is at least one in every coordinate. This problem is known to be NP-complete, and we are mainly interested in its on-line and off-line approximability. For the on-line version, we construct approximation algorithms with worst case guarantee arbitrarily close to 1/(2d) in d≥ 2 dimensions. This result contradicts a statement of Csirik and Frenk in [5] where it is claimed that, for d≥ 2 , no on-line algorithm can have a worst case ratio better than zero. Moreover, we prove that, for d≥ 2 , no on-line algorithm can have a worst case ratio better than 2/(2d+1) . For the off-line version, we derive polynomial time approximation algorithms with worst case guarantee Θ(1/ log d) . For d=2 , we present a very fast and very simple off-line approximation algorithm that has worst case ratio 1/2 . Moreover, we show that a method from the area of compact vector summation can be used to construct off-line approximation algorithms with worst case ratio 1/d for every d≥ 2 .
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00009203
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  • 3
    Electronic Resource
    Electronic Resource
    Interferon induction of (2′–5′) oligoisoadenylate synthetase in diploid and trisomy 21 human fibroblasts: Relation to dosage of the interferon receptor gene (IRFC) (1983)
    Springer
    Human genetics 〈Berlin〉 65 (1983), S. 108-111 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Trisomy 21 human fibroblasts are more sensitive to human interferon-α (IFN-α) than are diploid controls, consistent with the location of the gene (IFRC) which codes for the IFN-α receptor on chromosome 21. When compared in the antiviral assay, the difference in sensitivity is five-to tenfold, much greater then the 50% difference in IFRC gene dosage. An understanding of the mechanism by which this amplification of gene dosage occurs is relevant to the specific pathology of Down's syndrome and as a model system for studying the pathogenic effects of chromosomal aneuploidy. The enzyme (2′–5′) oligoisoadenylate synthetase (2–5A synthetase), which is believed to be central to the interferon-induced antiviral response, is induced 50% more in trisomy 21 fibroblasts than in diploid controls. Thus the amplification in response occurs subsequent to the binding of IFN-α to its receptor and the triggering of the first set of intracellular events, the latter exemplified by the induction of 2–5A synthetase. Similar results were obtained with IFN-γ, consistent with other evidence which indicates that a gene coding for a separate IFN-γ receptor is also located on chromosome 21.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00286644
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  • 4
    Electronic Resource
    Electronic Resource
    An attempt to explain the differences between the upper and lower halves of the striate cortical map of the cat's field of view (1984)
    Springer
    Biological cybernetics 49 (1984), S. 175-177 
    Details
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract Cowey and Rolls have shown that the magnification factor with which the retina is imaged onto the striate cortex is proportional to visual acuity. Schwartz has used this to derive how visual peripheral acuity in the human varies with distance from the fovea, in good agreement with experiment. The same reasoning applied to the map of the lower half of the field of view as imaged onto the striate cortex of the cat indicates that the cat fixating a point up to about 100 cm in front of him sees the foreground portion of the horizontal surface on which he is standing approximately uniformly blurred.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334463
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  • 5
    Electronic Resource
    Electronic Resource
    Different methods of assessing nicotine-induced antinociception may engage different neural mechanisms (1995)
    Springer
    Psychopharmacology 122 (1995), S. 301-306 
    Details
    ISSN: 1432-2072
    Keywords: Nicotine ; Mecamylamine ; Antinociception ; Chlorisondamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Two methods were used to assess nicotine-in-duced antinociception: tail withdrawal from a hot water bath and hind paw withdrawal from a hotplate. Nicotine doses which produced 75–80% maximum response were 0.75 mg/kg (free base) for tail withdrawal and 0.35 mg/kg for paw withdrawal. The peripheral blocker chlorisondamine (0.1 mg/kg, SC) and the central antagonist, mecamylamine (1 mg/kg, SC) were each effective in blocking nicotine-induced increases in tail withdrawal latencies, suggesting that this effect of nicotine depends on either the action of nicotine at peripheral receptors or the functional integrity of those receptors. In contrast, nicotine-induced increases in paw withdrawal latencies were blocked by mecamylamine but not by chlorisondamine, even at other agonist/antagonist dose combinations. The results indicate that these two effects of nicotine involve at least partially separate pathways and may reflect a different mix of the antinociceptive and motor depressing effects of nicotine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02246552
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  • 6
    Electronic Resource
    Electronic Resource
    Preparation and properties of stable protonation products of permethylmetallocenecarbaldehydes (M = Fe, Ru, Os) (1995)
    Springer
    Russian chemical bulletin 44 (1995), S. 2382-2389 
    Details
    ISSN: 1573-9171
    Keywords: nonamethylmetallocenecarbaldehydes ; iron ; ruthenium ; osmium ; molecular structure ; intramolecular hydrogen bond ; interionic hydrogen bond ; O-protonation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The products ofO-protonation of metallocenecarbaldehydes C5Me5MC5Me4CHO (M = Fe, Ru, Os) with HBF4 and CF3COOH were obtained for the first time, the adducts [C5Me5MC5Me4CH(OH)]+BF− being isolated in a pure state. The structures of the adducts depend on the nature of the metal and the anion and are governed by the correlation between their basicities. For example, the Fe-containing adducts have an open fulvenoid structure with an interionic hydrogen bond irrespective of the nature of the anion X (X = BF4 −, CF3COO−). In the case of the Ru- and Os-containing adducts in which the metal atoms are more basic than iron, the competition between the metal atom and the anion for the formation of a hydrogen bond with the OH group is clearly manifested in the IR and1H NMR spectra. In the presence of the weakly basic BF4 − anion, a cyclic structure with an intramolecular M...HO hydrogen bond is formed, while in the presence of a more basic F− or CF3COO− anion. it transforms to the open fulvenoid structure with an interionic hydrogen bond. The structures of the compounds obtained were determined by IR and1H NMR spectra, and the structure of the (C5Me5RuC5Me4CHOH)+...F− salt was proved by X-ray diffraction analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00713612
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  • 7
    Electronic Resource
    Electronic Resource
    The character of interaction of organometallic derivatives of 4-nitrophenol and 4-nitrothiophenol with anions in different media (1996)
    Springer
    Russian chemical bulletin 45 (1996), S. 1749-1752 
    Details
    ISSN: 1573-9171
    Keywords: molecular spectroscopy ; reaction of organometallic compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Interaction of R n M-derivatives of 4-nitrophenol and thiophenol (R n M= PhHG, PPh3Au, Ph3Sn, Ph4Sb) with a set of inorganic and organic anions (Cl−, Br−, I−, CN−, [PhOCO]−, [4-NO2C6H4OCO]−) was studied by IR and electronic spectroscopy in solvents with different polarities and coordinating properties (C6H6, CH2Cl2, DMSO). The dependence of the character of the interaction with the anions on the nature of the metal atom and heteroatom, the type of anions and the nature of the media was analyzed. Such interaction leads to ion-molecular complexes, and also to dissociation of the X-M bond (X = O, S, M = Au, Hg. Sb) with formation of the (4-NO2C6H4X)− anion even in weakly polar media. Only in the case of 4-NO2C6H4OSnPh3 does the reaction stop at the stage of complex formation. In other cases the role of complex formation with anions is less than with neutral coordinating reagents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01431819
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  • 8
    Electronic Resource
    Electronic Resource
    The structure ofO-arylmercury derivatives of dihydroxy-9,10-anthraquinones and their reactions with anions (1996)
    Springer
    Russian chemical bulletin 45 (1996), S. 2784-2791 
    Details
    ISSN: 1573-9171
    Keywords: IR spectroscopy ; electron spectroscopy ; hydroxyanthraquinone derivatives
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The structure of mono- and di-O-arylmercury-derivatives of quinizarin (1,4-dihydroxy-9, 10-anthraquinone) and anthrarufin (1,5-dihydroxy-9, 10-anthraquinone) and their reactions with Br−, Cl−, OH−, andtBuO− anions in the solid state and in aprotic solvents were examined by vibrational and electron spectroscopy. These reactions result in cleavage of the O-Hg bond. The formation of ions or contact ion pairs depends on the size and nature of the counterion; quinizarin dianions give very strong ion pairs with K+ cations, which do not cleave in DMSO. The electronic structure of mono- and dianions of the compounds studied is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01430643
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  • 9
    Electronic Resource
    Electronic Resource
    The repulsion algorithm, a new multistart method for global optimization (1996)
    Springer
    Structural and multidisciplinary optimization 11 (1996), S. 145-152 
    Details
    ISSN: 1615-1488
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract This paper proposes a new multistart algorithm to find the global minimum of constrained problems. This algorithm, which in this paper is called the repulsion algorithm, efficiently selects initial design points for local searches. A Bayesian approach provides the stopping rules. The method uses information from the previous sampling points and the corresponding sequences generated by local searches to select new initial points. This approach increases the probability of finding all local minima with fewer local searches. Numerical example problems show that compared with traditional multistart methods, the repulsion algorithm reduces significantly the number of local searches required to find the global minimum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01197028
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