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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of philosophical logic 28 (1999), S. 165-174 
    ISSN: 1573-0433
    Keywords: foundations of arithmetic ; predicativism ; finiteness ; natural numbers ; induction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Philosophy
    Notes: Abstract Recently, Feferman and Hellman (and Aczel) showed how to establish the existence and categoricity of a natural number system by predicative means given the primitive notion of a finite set of individuals and given also a suitable pairing function operating on individuals. This short paper shows that this existence and categoricity result does not rely (even indirectly) on finite-set induction, thereby sustaining Feferman and Hellman's point in favor of the view that natural number induction can be derived from a very weak fragment of finite-set theory, so weak that finite-set induction is not assumed. Many basic features of finiteness fail to hold in these weak fragments, conspicuously the principle that finite sets are in one-one correspondence with a proper initial segments of a (any) natural number structure. In the last part of the paper, we propose two prima facie evident principles for finite sets that, when added to these fragments, entail this principle.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    European archives of psychiatry and clinical neuroscience 107 (1938), S. 580-598 
    ISSN: 1433-8491
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zusammenfassung 1. Die Tapping- und Metronomtempi, yon einigen Forschern Ms Indicatoren eines alle Handlungen durchdringenden p.T. angesehen, werden fiber einen Zeitraum yon etwa 7 Monaten hin regelmäßig untersucht, und zwar bei Normalen und bei Pat. mit verschiedenen Arten voI) Depressionen: endogenen, chronischen, reaktiven und klimakterisehen Depressionen. 2. Sowohl bei den Normalen als auch bei den Pat. mit endogenen Depressionen besteht eine sehr hohe Korrelation zwischen Tapping- und Metronomwerten. 3. Zwischen den Tapping- und Metronomwerten einerseits und dem pathologisch veränderten psychischen, insbesondere affektiven Zustand andererseits, lassen sieh gewisse Zusammenhänge nachweisen: die Depression senkt beide Werte and die innere Spannung oder Unruhe erhTht die Tappingwerte. Bei den FAllen, we diese Unruhe neben der Depression eine grol3e Rolle spielt (reaktive, klimakterische Depressionen) finder man demznfolge eine Dissoziation der Tapping- und Metronomwerte. 4. Bei don Norma,len zeigen beide Werte eine weitgehende Konstanz. 5. Bei den endogenen Depressionen bleibt diese Konstanz im Laufe der Psyehose erhalten. Die Veränderungen im klinisehen Bilde werden yon einer stetigen Zu- oder Abnahme der Werte begleitet. 6. Bei don reaktiven Depressionen weisen beide Werte eine großbe Labilität auf, deren Zusammenhang mit dem psychischen Zust~nd sich nieht immer verfolgen läßt; dasselbe gilt ffir die chronisehen und fiir die größere Zahl der kIimakterisehen Depressionen. Bei den reaktiven Depressionen bringt die Heilung ein Schwinden dieser Labilität hervor, was sich in einer Stabflisierung der Kurven ausdrückt. Die Zunahme der Werte bei der Remission kommt auch hier deutlich zum Vorschein.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Archive for mathematical logic 33 (1994), S. 283-289 
    ISSN: 1432-0665
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary We introduce a class of models of the bounded arithmetic theoryPV n . These models, which are generated by their tally part, have a curious feature: they have end-extensions or satisfyB∑ n b only in case they are closed under exponentiation. As an application, we show that if then the polynomial hierarchy does not collapse.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1572-9702
    Keywords: rabbit tick ; Haemaphysalis leporis-palustris ; ixodidae ; life cycle ; Sylvilagus brasiliensis ; Oryctolagus cuniculus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The life cycles of two separate populations (colonies A and B) of the rabbit tick, Haemaphysalis leporis-palustris, were studied under laboratory conditions. Domestic New Zealand rabbits, Oryctolagus cuniculus, and wild rabbits, Sylvilagus brasiliensis, were used as hosts for ticks from colony B and only O. cuniculus rabbits were used as hosts for ticks from colony A. Developmental periods were observed in an incubator at 27 ± 1°C and RH 90 ± 5%. Larvae from colonies A and B fed for 8.0 ± 3.7 days and 8.5 ± 1.3 days, respectively, on O. cuniculus. On S. brasiliensis larvae from colony B fed for 7.2 ± 1.3 days. Nymphs from colony A fed for 8.1 ± 1.4 days on O. cuniculus and nymphs from colony B fed for 8.1 ± 1.0 days on S. brasiliensis. Only one engorged nymph from colony B was recovered from O. cuniculus. Females from colony A fed for 20.9 ± 5.9 days on O. cuniculus and females from colony B fed for 18.6 ± 2.4 days on O. cuniculus and 18.7 ± 3.7 days on S. brasiliensis. Engorged larvae from colony A required 13.7 ± 3.7 days to molt while engorged larvae from colony B required 11.8 ± 3.0 and 11.5 ± 1.8 days to molt, after having fed on O. cuniculus and S. brasiliensis, respectively. Engorged nymphs from colonies A and B required 16.3 ± 1.9 days and 14.7 ± 1.4 days to molt, respectively. Engorged females from colonies A and B required 4–7 and 3–5 days, respectively, to start oviposition. Mean egg incubation periods lasted for 33–34 days. For ticks from colony B, host species accounted for significant differences (p 〈 0.05) in larval and nymphal feeding periods, oviposition weights and CEIs. Significant differences (p 〈 0.05) between the two colonies when ticks fed on O. cuniculus were observed for larval and nymphal feeding and premolt periods, engorged female and oviposition weights and conversion efficiency indexes (CEI). S. brasiliensis were always a more suitable host for H. leporis-palustris than O. cuniculus. Significantly more larvae and nymphs engorged and molted when fed on S. brasiliensis (p 〈 0.001). Females fed S. brasiliensis were more successful to lay fertile eggs and showed the highest engorged and egg mass weights, and the highest CEIs. Data of H. leporis-palustris fed on wild rabbits (one of its natural host species) are reported for the first time.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-1561
    Keywords: Macrosiphum euphorbiae ; Homoptera (Aphididae) ; Solanum tuberosum ; Solanaceae ; potato ; α-chaconine ; α-solanine ; α-tomatine ; solanidine ; tomatidine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Macrosiphum euphorbiae, also known as the potato aphid, is a potato virus vector, associated with decreased tuber production. Feeding, toxicity, and reproductive effects of the major potato glycoalkaloids (α-chaconine and α-solanine), their common aglycone (solanidine), and a nonpotato glycoalkaloid (α-tomatine) and its aglycone (tomatidine) onM. euphorbiae were studied. As expected, neither α-chaconine nor α-solanine had a strong lethal effect on the aphid, but α-chaconine stimulated feeding at low concentrations. Both aglycones were deterrent and lethal at high concentrations and, like α-chaconine and α-tomatine, they delayed the appearance and decreased the number of nymphs.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-1561
    Keywords: Schizaphis graminum ; Aphididae ; aphids ; greenbug ; survival ; glycosides ; glycoalkaloids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Common Solanum glycosides were tested against a non-Solanum pest, the greenbug, Schizaphis graminum, fed by artificial diet supplemented with the tested compounds. In contrast with the potato aphid Macrosiphum euphorbiae, S. graminum is sensitive to both potato and tomato glycoalkaloids, as well as to all the different Solanum steroidal glycosides tested. S. graminum was less sensitive to glycoalkaloids than to the steroidal glycosides. Laxumin A (LC50 4.3 μM) and laxumin B (LC50 6.1 μM), isolated from Solanum laxum, were the most active of the tested compounds. The different sensitivity of both aphids against Solanum glycosides could be related to a possible adaptation of the insects to their host plants secondary metabolites.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-1561
    Keywords: Macrosiphum euphorbiae ; potato aphid ; Homoptera ; Aphididae ; Solanaceae ; glycoalkaloids ; bioassay ; commersonine ; demissine ; solamargine ; solasodine ; solasonine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We report the deterrent, toxic, and antireproductive effect of several Solanum glycoalkaloids on the potato aphid, Macrosiphum euphorbiae, and discuss the structure–activity relationship of the tested compounds. The results indicate a structure-dependent biological effect of the glycoalkaloids, suggesting that, while the structure of the aglycone defines a basal biological effect, the carbohydrate moiety is crucial for the overall biological effect.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1573-5060
    Keywords: Solanum ; tomatine ; commersonine ; demissine ; dehydrocommersonine ; dehydrodemissine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Five glycoalkaloids were identified from the aerial parts of wild Solanum commersonii Dun. ex Poir growing in Uruguay and their structures elucidated mainly by chemical and spectroscopic methods. In addition to the already known commersonine, demissine, tomatine and dehydrocommersonine, a new glycoalkaloid, identified as δ5-demissine, solanid -5-en-3-O- {β-D-Glcp-(1→2)-[β-D-Xylp-(1→3) ]β-D-Glcp-(1→4)-β-D-Galp } was found. Tomatine and dehydrocommersonine have not been reported earlier as components of this plant. The glycoalkaloid composition found in the wild plants studied differ significatively from those described earlier, and have some implications in taxonomy and its use in potato breeding.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of applied phycology 6 (1994), S. 199-210 
    ISSN: 1573-5176
    Keywords: cyanobacteria ; iron deficiency ; photosynthesis ; siderophores ; flavodoxin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Iron is an essential component of electron transport in almost all living organisms. It is particularly important to phototrophs like cyanobacteria because 22–23 irons are required for a complete functional photosynthetic apparatus. Since the low solubility of Fe+++ above neutral pH in oxic ecosystems severely limits the biological availability of iron to aquatic microorganisms, cyanobacteria and other microbes have developed a number of responses to cope with iron deficiency. Cyanobacterial responses to iron stress include the synthesis of an efficient, siderophore-based system to scavenge iron and the substitution of ferredoxin with flavodoxin. An additional response in cyanobacteria involves the alteration of the light-harvesting apparatus that includes the appearance of a new, iron-stress-induced, photosystem II, chlorophyll-binding protein. Although cytochromec-553 has a potential non-iron-containing replacement in plastocyanin, a copper-containing protein, iron stress appears to favor the utilization of cytochromec-553 because siderophores also bind copper and form a complex that is excluded from the cell. This paper is intended primarily as a review of molecular and physiological responses of actively growing cyanobacterial cultures to conditions of iron stress, where iron is present but essentially insoluble, and to differentiate these responses from iron starvation, where the amount of iron in the system is not sufficient for cell growth.
    Type of Medium: Electronic Resource
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