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  • Infinite-horizon optimal control  (3)
  • Muscidae  (3)
  • Thioredoxin  (2)
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  • 1
    Electronic Resource
    Electronic Resource
    Contrasting modes of photosynthetic enzyme regulation in oxygenic and anoxygenic prokaryotes (1984)
    Springer
    Archives of microbiology 139 (1984), S. 124-129 
    Details
    ISSN: 1432-072X
    Keywords: Photosynthesis ; Regulation ; Thioredoxin ; Cyanobacterium ; Chromatium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Enzymes that are regulated by the ferredoxin/thioredoxin system in chloroplasts — fructose-1,6-bisphosphatase (FBPase), sedoheptulose-1,7-bisphosphatase purified from two different types of photosynthetic prokaryotes (cyanobacteria, purple sulfur bacteria) and tested for a response to thioredoxins. Each of the enzymes from the cyanobacterium Nostoc muscorum, an oxygenic organism known to contain the ferredoxin/thioredoxin system, was activated by thioredoxins that had been reduced either chemically by dithiothreitol or photochemically by reduced ferredoxin and ferredoxin-thioredoxin reductase. Like their chloroplast counterparts, N. muscorum FBPase and SBPase were activated preferentially by reduced thioredoxin f. SBPase was also partially activated by thioredoxin m. PRK, which was present in two regulatory forms in N. muscorum, was activated similarly by thioredoxins f and m. Despite sharing the capacity for regulation by thioredoxins, the cyanobacterial FBPase and SBPase target enzymes differed antigenically from their chloroplast counterparts. The corresponding enzymes from Chromatium vinosum, an anoxygenic photosynthetic purple bacterium found recently to contain the NADP/thioredoxin sytem, differed from both those of cyanobacteria and chloroplasts in showing no response to reduced thioredoxin. Instead, C. vinosum FBPase, SBPase, and PRK activities were regulated by a metabolite effector, 5′-AMP. The evidence is in accord with the conclusion that thioredoxins function in regulating the reductive pentose phosphate cycle in oxygenic prokaryotes (cyanobacteria) that contain the ferredoxin/thioredoxin system, but not in anoxygenic prokaryotes (photosynthetic purple bacteria) that contain the NADP/thioredoxin system. In organisms of the latter type, enzyme effectors seem to play a dominant role in regulating photosynthetic carbon dioxide assimilation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00401986
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  • 2
    Electronic Resource
    Electronic Resource
    The ferredoxin/thioredoxin system of enzyme regulation in a cyanobacterium (1981)
    Springer
    Archives of microbiology 130 (1981), S. 14-18 
    Details
    ISSN: 1432-072X
    Keywords: Thioredoxin ; Cyanobacterium ; Ferredoxin ; Nostoc ; Regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cell-free preparations of the cyanobacterium (bluegreen alga) Nostoc muscorum were assayed for thioredoxins and enzymes catalyzing the ferredoxin and NADP-linked reduction of thioredoxin. Nostoc was found to have two different thioredoxins: one of approximate molecular weight 16,000 (designated Nostoc thioredoxin f) that selectively activated chloroplast fructose 1,6-bisphosphatase, and another of approximate molecular weight 9,000 (designated Nostoc thioredoxin m) that selcetively activated chloroplast NADP-malate dehydrogenase. The two thioredoxins could be reduced either chemically with dithiothreitol or photochemically with ferredoxin and ferredoxin-thioredoxin reductase which, like the recently found regulatory iron-sulfur protein ferralterin, was present in Nostoc cells. Nostoc ferredoxin-thioredoxin reductase appeared to be similar to its chloroplast counterpart in enzyme specificity, molecular weight, and spectral properties. The Nostoc and spinach chloroplast ferredoxin-thioredoxin reductases as well as their thioredoxins, ferredoxins, and chlorophyll containing membranes were interchangeable in activating chloroplast fructose 1,6-bisphosphatase and NADP-malate dehydrogenase. There was no evidence for an NADP-linked thioredoxin reductase such as that of E. coli. The results are in accord with the conclusion that the cyanobacteria resemble higher plants in having a functional ferredoxin/thioredoxin system rather than an NADP/thioredoxin system typical of other bacteria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00527065
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  • 3
    Electronic Resource
    Electronic Resource
    Uniformly overtaking and weakly overtaking optimal solutions in infinite-horizon optimal control: When optimal solutions are agreeable (1990)
    Springer
    Journal of optimization theory and applications 64 (1990), S. 55-69 
    Details
    ISSN: 1573-2878
    Keywords: Infinite-horizon optimal control ; overtaking optimal solutions ; decision-horizon optimal solutions ; agreeable plans ; sufficient conditions for optimality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract In this paper, we investigate the relationship between two classes of optimality which have arisen in the study of dynamic optimization problems defined on an infinite-time domain. We utilize an optimal control framework to discuss our results. In particular, we establish relationships between limiting objective functional type optimality concepts, commonly known as overtaking optimality and weakly overtaking optimality, and the finite-horizon solution concepts of decision-horizon optimality and agreeable plans. Our results show that both classes of optimality are implied by corresponding uniform limiting objective functional type optimality concepts, referred to here as uniformly overtaking optimality and uniformly weakly overtaking optimality. This observation permits us to extract sufficient conditions for optimality from known sufficient conditions for overtaking and weakly overtaking optimality by strengthening their hypotheses. These results take the form of a strengthened maximum principle. Examples are given to show that the hypotheses of these results can be realized.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00940022
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  • 4
    Electronic Resource
    Electronic Resource
    Infinite-horizon optimal controls for problems governed by a volterra integral equation with state-and-control-dependent discount factor (1990)
    Springer
    Journal of optimization theory and applications 66 (1990), S. 311-336 
    Details
    ISSN: 1573-2878
    Keywords: Infinite-horizon optimal control ; Volterra integral equations ; recursive objective functionals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract In this work, we concern ourselves with the existence of optimal solutions to optimal control problems defined on an unbounded time interval with states governed by a nonlinear Volterra integral equation. These results extend both the work of Baum and others in infinite-horizon control of ordinary differential equations as well as the work of Angell concerning integral equations. In addition, we incorporate into the objective functional (described by an improper integral) a discount factor which reflects a hereditary dependence on both state and control. In this manner, we are able to generalize the recent results of Becker, Boyd, and Sung in which they establish an existence theorem in the calculus of variations with objective functionals of the so-called recursive type. Our results are obtained through the use of appropriate lower-closure theorems and compactness conditions. Examples are presented in which the applicability of our results is demonstrated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00939541
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  • 5
    Electronic Resource
    Electronic Resource
    Nonconvex and relaxed infinite-horizon optimal control problems (1993)
    Springer
    Journal of optimization theory and applications 78 (1993), S. 465-491 
    Details
    ISSN: 1573-2878
    Keywords: Infinite-horizon optimal control ; overtaking optimality ; economic growth ; chattering states
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract In this paper, we consider the Lagrange problem of optimal control defined on an unbounded time interval in which the traditional convexity hypotheses are not met. Models of this form have been introduced into the economics literature to investigate the exploitation of a renewable resource and to treat various aspects of continuous-time investment. An additional distinguishing feature in the models considered is that we do not assume a priori that the objective functional (described by an improper integral) is finite, and so we are led to consider the weaker notions of overtaking and weakly overtaking optimality. To treat these models, we introduce a relaxed optimal control problem through the introduction of chattering controls. This leads us naturally to consider the relationship between the original problem and the convexified relaxed problem. In particular, we show that the relaxed problem may be viewed as a limiting case for the original problem. We also present several examples demonstrating the applicability of our results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00939878
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  • 6
    Electronic Resource
    Electronic Resource
    Contact sex pheromone in the tsetse flyGlossina pallidipes (Austen) Identification and Synthesis (1984)
    Springer
    Journal of chemical ecology 10 (1984), S. 429-450 
    Details
    ISSN: 1573-1561
    Keywords: Glossina ; pallidipes ; tsetse fly ; Diptera ; Muscidae ; pheromone ; contact stimulant ; branched alkane ; 13,23-dimethylpentatriacontane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Adult maleG. pallidipes attempted to copulate with decoys treated with a branched paraffin obtained from laboratory-reared female flies. The compound causing maximal response was isolated and identified as 13,23-dimethylpentatriacontane. The synthesized compound elicited increasing responses with increasing doses. This sex- and species-specific compound was always present in physiological amounts in females, as it increased from 2 μg at emergence to 10 μg per female at 14 days. It was present in wild-caught females from a wide geographical range.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00988090
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  • 7
    Electronic Resource
    Electronic Resource
    Polyunsaturated hydrocarbons in the stable fly (1985)
    Springer
    Journal of chemical ecology 11 (1985), S. 1485-1496 
    Details
    ISSN: 1573-1561
    Keywords: Stable fly ; Stomoxys calcitrans ; Diptera ; Muscidae ; hydrocarbons ; olefins ; (Z,Z)-1,7,13-pentacosatriene ; (Z,Z)-1,7,13-tetracosatriene ; (Z,Z)-1,7,13-tricosatriene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Three triply-unsaturated hydrocarbons were identified from cuticular lipids of male and mixed-sex stable flies,Stomoxys calcitrans. The major compound, (Z,Z)-1,7,13-pentacosatriene, and two minor compounds, (Z,Z)-1,7,13-tetracosatriene and (Z,Z)-1,7,13-tricosatriene, were synthesized. Samples of male and female stable flies that differed in age, seasonality, geographic origin, rearing conditions of adults, and methods of extraction were analyzed for the presence of these triolefins. Females were found to have small quantities of the same C25 triolefin, which appeared to be identical to that in males. No evidence was seen for attraction of males or females to natural or synthetic triolefins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01012194
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  • 8
    Electronic Resource
    Electronic Resource
    Unusual polymethyl alkenes in tsetse flies acting as abstinon inGlossina morsitans (1991)
    Springer
    Journal of chemical ecology 17 (1991), S. 267-284 
    Details
    ISSN: 1573-1561
    Keywords: Mating inhibitor ; abstinon ; stimulatory ; cuticle waves ; diptera ; extract ; hydrocarbon ; dimethylalkene ; trimethylalkene ; aphrodisiac ; Diptera ; Muscidae ; Glossina morsitans morsitans ; tsetse fly ; 19,23-dimethyltritriacont-1-ene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The major alkene of the male tsetse fly,Glossina morsitans morsitans, was isolated for characterization by thin-layer and gas chromatography (GC). The mass spectra of the alkene and the alkene DMDS derivative indicated one isomer, 19,23-dimethyltritriacont-1-ene. The material is present at 1–2μg/male fly and is partially transferred to the female preparatory to or during mating. A dose-dependent antiaphrodisiac effect was seen with exposed male flies using the isolated natural product, with 2 and 4μg causing 80% loss of copulatory attempts, and 10μg extinguishing the attempts. This effect was increased by addition of male-produced alkane. This compound and a 31-carbon homolog also appear inG. m. submorsitans. Similar quantities of alkenes that are species-specific appear in all tsetse males. Structures of male-produced trimethylalkenes that appear in two other species,G. palpalis palpalis andG. fuscipes fuscipes, were investigated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00994332
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