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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Journal of ornithology 140 (1999), S. 81-86 
    ISSN: 1439-0361
    Schlagwort(e): Reed Warbler ; timing of breeding ; spring arrival ; global climate change ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung In einem Untersuchungsgebiet am westlichen Bodensee (Halbinsel Mettnau) zeichnet sich zwischen 1976 und 1997 eine deutliche Zunahme früh ausgeflogener Teichrohrsänger ab, was auf ein früheres Brüten schließen läßt. Weiterhin hat sich die Erstankunft des Teichrohrsängers am Bodensee in den letzten 16 Jahren (1982–1997) im Vergleich zum Zeitraum 1961 bis 1980 um genau eine Woche verfrüht (im Mittel vom 26.4. auf den 19.4.). Während sich zwischen der jährlichen Erstankunft des Teichrohrsängers am Bodensee und der Zahl früh ausgeflogener Jungvögel kein statistisch gesicherter Zusammenhang finden läßt, ist die Temperatur in der ersten Maihälfte ein guter (statistisch signifikanter) Indikator für die Zahl früh ausgeflogener Teichrohrsänger. Die vorliegende Untersuchung zeigt, daß sich offenbar auch Langstreckenzieher an die sich abzeichnende Klimaveränderung anzupassen beginnen.
    Notizen: Summary Data from a standardized mist-netting programme (the so-called "MRI-Programm") were used to assess the timing of breeding in Reed Warblers (Acrocephalus scirpaceus) at Lake Constance (South Germany). The number of Reed Warblers fledged early in the season increased significantly between 1976 and 1997 (rs=0.614; p〈0.01). This is most probably due to a long-term increase in spring temperature as suggested by the high correlation between the number of early-fledged Reed Warblers and mean temperature in the first half of May (rs=0.416; p〈0.01). While in the period from 1961 to 1980 the mean date of spring arrival was on the 26th of April, it shifted towards the 19th April from 1981 to 1997. However, the number of early-fledged Reed Warblers and the date of spring arrival are not significantly correlated. The lack of a significant correlation may be due to a number of reasons, for instance early arriving birds do not belong to the local population or there could be an observational bias among years. Yet, the most likely explanation is that the timing of breeding in Reed Warblers is triggered by vegetation growth and food supply rather than by the timing of spring arrival. There is growing body of evidence from this and other studies that the recent climate change is responsible for the shift in both the timing of migration and breeding in birds.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 93 (1999), S. 149-155 
    ISSN: 1570-7458
    Schlagwort(e): Megalurothrips sjostedti ; temperature ; photoperiod ; development ; pre-oviposition ; oviposition ; diapause
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Megalurothrips sjostedti is an economic pest of cowpea in tropical Africa. There are no reports of the effect of temperature on the development of the pest and no diapause has been detected. The developmental rate and reproduction of M. sjostedti was studied under six constant temperatures (14, 17, 20, 23, 26 and 29 °C ) and a photoperiod of L12:D12 in the laboratory. Total developmental time ranged from 33.1 days at 14 °C to 19.2 days at 26 °C. At 29 °C, all larvae died during hatching. Egg, larval and pupal stages required 94.3, 97.1 and 105.3 deg-days (DD) above a threshold of 8.2, 9.1 and 10.4 °C, respectively, to complete development. Total developmental cycle was completed at 163.9 DD above a threshold of 12.6 °C. Adult longevity was lowest (11.1 days) at 29 °C and highest (28.7 days) at 14 °C. At constant temperatures, the highest pre-oviposition period was observed at 29 °C under a photoperiod of L16:D8. Egg production also ceased at this temperature/photoperiod combination. Total fecundity was highest at 26 °C under L10:D14. At cyclical temperatures, pre-oviposition period was longest (12.4 days) at 20/29 °C under L16:D8. Total fecundity was highest (168.4 eggs) at 14/26 °C under L10:D14, and lowest (8.2 eggs) at 20/29 °C under L16:D8. The significance of these findings in the management of M. sjostedti is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 90 (1999), S. 25-35 
    ISSN: 1570-7458
    Schlagwort(e): Aphis gossypii ; development ; survival ; fecundity ; intrinsic rate of increase ; life table ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Life table parameters of Aphis gossypii Glover (Homoptera: Aphididae) on Gossypium hirsutum L. were determined at six temperatures (10, 15, 20, 25, 30, and 35 ± 0.5 °C) in the laboratory. Relationships of life table parameters with temperature were described with mathematical equations. Development was fastest at 30 °C, with a pre-larviposition period of 4.6 d. Survival to adult was greatest at 25 °C (81%). Fecundity was highest at 25 °C, with a total fecundity of 28.3 nymphs per female and a mean reproductive rate of 3.1 nymphs per female per day. Threshold temperatures for development in the first through fourth instar and the adult were 8.2, 8.0, 7.2, 6.2 and 7.9 °C, respectively. The durations of these stages, expressed as temperature sums above these thresholds, were 24.2, 23.7, 23.0, 25.5 and 168.8 degree-days (D°), respectively. A. gossypii achieved its maximum net reproductive number (24.4 nymphs per female) and greatest intrinsic rate of increase (0.386 d−1) at 25 °C. The high relative rate of population increase at 25 °C results in a daily population increase of 47% and a doubling time of only 1.8 d, illustrating the tremendous growth capacity of A. gossypii populations under favourable conditions. Compared to literature sources, our source of A. gossypii, fed on cotton, showed a comparatively great heat tolerance.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 93 (1999), S. 297-302 
    ISSN: 1570-7458
    Schlagwort(e): smaller fruit tortrix ; Grapholita lobarzewskii ; phenology ; post-diapause development ; temperature ; thermal threshold ; thermal constant ; forecasting ; modelling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The smaller fruit tortrix, Grapholita lobarzewskii Nowicki, has become a major pest in the recent past in apple orchards north of the Alps. Nevertheless little is known about the biology and the behaviour of this species. The effect of temperature on post-diapause development and survival was studied under controlled conditions in order to establish a basis for the forecasting of adult emergence. Survival was found to be highest at 17 °C and lowest at 11.8 °C. The sex ratio did not differ significantly from 1:1. Based on a linear relationship between temperature and developmental rates, thermal thresholds of 9.6 °C and 9.8 °C were determined for females and males respectively. The thermal constants, i.e., the mean developmental times in physiological time units, were found to be 342 day-degrees for females and 317 day-degrees for males, suggesting a slight protandry. Based on the mean and the variance of the developmental times, a simple temperature-driven phenology model was built using a time-varying distributed delay. The model was validated by visually comparing the predictions with independent observations on adult emergence, and by calculating the temporal deviations of the predictions. In 4 out of 5 years the mean error was less than 3 days. The model was therefore found to give reliable forecasts of the emergence of G. lobarzewskii and can be used to determine the optimal time for the exposure of pheromone traps, the application of pheromone dispensers for mating disruption, and for the timing of insecticide applications.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Journal of polymers and the environment 7 (1999), S. 101-108 
    ISSN: 1572-8900
    Schlagwort(e): Polylactic acid ; temperature ; respirometers ; soil degradation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Energietechnik , Maschinenbau
    Notizen: Abstract A respirometric system was used to analyze the biodegradation of high molecular weight (120,000 to 200,000 g mol−1) polylactic acid (PLA) plastic films in soil under laboratory conditions. The respirometric system consisted of air-conditioning pretraps, a soil reactor, and a carbon dioxide (CO2) posttrap. A 200-g homogeneous soil mixture of all-purpose potting soil : manure soil : sand [1 : 1 : 1 (w/w)] and 1.5 g of PLA plastic films in 1 × 1-cm2 squares was added to each bottle. The respirometers were placed in a 28, 40, or 55°C water bath for 182 days. Treatments (three replicates) included native corn starch (positive control), polyethylene (Glad Cling Wrap; negative control), and three PLA films: Ca-I (Cargill Dow Polymers LLC, monolayer), GII (Cargill Dow Polymers LLC, Generation II), and Ch-I (Chronopol; monolayer). The degree of polymer mineralization was indicated by the cumulative CO2 liberated from each respirometer. The initial average mineralization rate and total percentage mineralized of the PLA plastic films at 28, 40, and 55°C was 24.3, 41.5, and 76.9 mg/day with a 27, 45, and 70% carbon loss, respectively. No decrease in soil pH was observed after 182 days of mineralization. Hence, increase in soil temperature drastically enhanced the biodegradation of PLA plastic films in soil under laboratory conditions (P 〈 0.0001).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Journal of polymers and the environment 7 (1999), S. 83-92 
    ISSN: 1572-8900
    Schlagwort(e): Polylactic acid ; temperature ; relative humidity ; degradation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Energietechnik , Maschinenbau
    Notizen: Abstract Three high molecular weight (120,000 to 200,000 g mol−1) polylactic acid (PLA) plastic films from Chronopol (Ch-I) and Cargill Dow Polymers (GII and Ca-I) were analyzed for their degradation under various temperature and relative humidity (RH) conditions. Two sets of plastic films, each containing 11 samples, were randomly hung in a temperature/humidity-controlled chamber by means of plastic-coated paper clips. The tested conditions were 28, 40, and 55°C at 50 and 100% RH, respectively, and 55°C at 10% RH. The three tested PLA films started to lose their tensile properties when their weight-average molecular weight (M w) was in the range of 50,000 to 75,000 g mol−1. The average degradation rate of Ch-I, GII, and Ca-I was 28,931, 27,361, and 63,025 M w/week, respectively. Hence, GII had a faster degradation rate than Ch-I and Ca-I under all tested conditions. The degradation rate of PLA plastics was enhanced by the increase in temperature and relative humidity. This trend was observed in all three PLA plastics (Ca-I, GII, and Ch-I). Of the three tested films, Ch-I was the first to lose its mechanical properties, whereas Ca-I demonstrated the slowest loss, with mechanical properties under all tested conditions.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Journal of applied electrochemistry 29 (1999), S. 81-85 
    ISSN: 1572-8838
    Schlagwort(e): cupric oxide ; powder ; current density ; temperature ; sodium sulfate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Abstract Electrosynthesis of cupric oxide powder was carried out on a laboratory scale in an electrochemical cell under various experimental conditions. The electrolysis was appraised in terms of the particle size of the cupric oxide product and the anodic dissolution of the copper electrode. Using a previously determined pH value of 7.50, the other optimum electrolysis operating conditions established were a current density of 4000Am−2, temperature of 353K, and Na2SO4 concentration of 0.5m. The optimum values of current efficiency, cell voltage and specific energy consumption for the electrochemical synthesis of cupric oxide powder were determined.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Journal of applied electrochemistry 29 (1999), S. 525-528 
    ISSN: 1572-8838
    Schlagwort(e): brine ; chlor-alkali cells ; solubility ; sulfate ions ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Elektrotechnik, Elektronik, Nachrichtentechnik
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Journal of heuristics 5 (1999), S. 145-158 
    ISSN: 1572-9397
    Schlagwort(e): evolutionary algorithms ; genetic algorithms ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract This paper shows how evolutionary algorithms can be described in a concise, yet comprehensive and accurate way. A classification scheme is introduced and presented in a tabular form called TEA (Table of Evolutionary Algorithms). It distinguishes between different classes of evolutionary algorithms (e.g., genetic algorithms, ant systems) by enumerating the fundamental ingredients of each of these algorithms. At the end, possible uses of the TEA are illustrated on classical evolutionary algorithms.
    Materialart: Digitale Medien
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  • 10
    ISSN: 1573-0417
    Schlagwort(e): diatoms ; temperature ; sediment traps ; seasonal succession ; resuspension ; Lake Holzmaar
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie
    Notizen: Abstract The seasonal sedimentation pattern of diatom valves in Lake Holzmaar was investigated during 1995 by deploying sediment traps at three different lake depths. According to the sedimentation pattern, the major reproduction zone of diatoms was restricted to the upper 6 m of the water body. The population growth started late in April and blooms of Cyclotella cf. comensis Grun., which dominates the plankton diatoms, and Fragilaria crotonensis Kitton were collected in traps during June and September, and July, respectively. During summer, the seasonal sedimentation pattern of each taxon, as collected in the upper traps, was reflected in the concentrations in the lowest trap. However, in May and from September onwards, the community composition in the lowest trap and augmented trapping rates suggest both sediment focusing and resuspension of bottom sediments. The temperature signals as recorded by δ18O values of diatom valves should, therefore, reflect integrated temperatures between 0 and 6 m depth. However, temperatures during summer and autumn are expected to be accentuated in the sedimentary record since the isotopic signal is weighted by both the number and the weight-mass of the valves. During summer, the transfer of these signals by the sedimenting diatoms retains the information pattern recorded, while in spring and autumn/winter additional influxes caused by resuspension may somewhat alter those temperature informations. The proxy signals finally stored in the sediments, may, therefore, not precisely represent the successive temperatures currently recorded during 1995 within mid-lake.
    Materialart: Digitale Medien
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  • 11
    ISSN: 1573-0832
    Schlagwort(e): interspecific interactions ; ochratoxin ; Aspergillus ochraceus ; spoilage fungi ; water relations ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The effect of water availability (water activity,aw; 0.995–0.90) and temperature (18–30 °) on in vitro interactions between an ochratoxin producing strain of Aspergillus ochraceus and six other spoilage fungi was assessed in dual culture experiments on a maize meal-based agar medium. Inprimary resource capture of nutrient substrate, A. ochraceus was dominant against many of the interacting species, being able to overgrow and replace A. candidus, and sometimes A. flavus and the Eurotium spp. regardless of aw or temperature. However, with freely available water (0.995 aw) A. alternata and A. niger were dominant, with mutual antagonism between A. ochraceus and A. flavus at 25–30 °C. In the driest conditions tested (0.90 aw) there was also mutual antagonism between A. ochraceus and the two Eurotium spp. Overall, under allconditions tested the Index of Dominance for A. ochraceus was much higher than for other competing species combined suggesting that A. ochraceus wasa good competitive colonist able to replace a numberof other species. However, the growth rate ofA. ochraceus was modified and decreased by the interaction with competitors. Interaction between A. ochraceus and species such as A. alternata (18°C/0.995) and Eurotium spp. (0.995–0.95 and 25–30 °C) resulted in a significant stimulation of ochratoxin production. Theresults are discussed in relation to the effect that environmental factors have on the possible competitiveness of A. ochraceus in the maizegrain ecosystem and the role of ochratoxin in nicheexclusion of competitors.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Experimental and applied acarology 23 (1999), S. 669-679 
    ISSN: 1572-9702
    Schlagwort(e): Panonychus ulmi ; dipause eggs ; overwintering ; dipause termination ; temperature ; photoperiod
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In apple orchards in northern Greece, females of Panonychus ulmi Koch were found to lay diapause eggs from late August to the beginning of October. The course of diapause termination in the field was determined by transferring diapause eggs during winter and early spring from apple orchards with the varieties ‘Starkinson’ and ‘Firiki’ to short days (LD 8:16) (1992–1996), and long days (LD 16:8) (1994–1995), both at 20 °C. Percentages of diapause termination were very low to zero from October to the beginning of January, then progressively increased throughout January and February. Diapause termination in 50% of the eggs occurred in the first half of February in lowland mite populations irrespective of the year and location from which the eggs originated, and about one month earlier in a population originating from an altitude of 300 m. For each sampling date throughout the winter, the mean number of days required for 50% egg hatch at 20 °C (T50%) was similar under either a long (LD 16:8) or a short (LD 8:16) photoperiod. Diapause eggs collected in October 1995 from two orchards and maintained at 0, 5, 10 and 15 °C for various periods were subsequently transferred to 20 °C and LD 8:16, where TP50% was determined. It was shown that temperature, duration of maintenance at the different temperatures and the orchard from which the eggs originated had a significant effect on T50% and therefore on diapause development. Additionally, in our strains diapause intensity was much weaker than in strains from more northern latitudes and was terminated even without any cold exposure. The variation in diapause intensity in different strains of P. ulmi may have an adaptive significance for this widespread species.
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Journal of the history of biology 32 (1999), S. 509-555 
    ISSN: 1573-0387
    Schlagwort(e): Louis Agassiz ; Spencer Baird ; Charles Girard ; reputation ; taxonomy ; ichthyology ; Museum of Comparative Zoology ; Smithsonian Institution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geschichte
    Notizen: Abstract The reputations of scientists among their contemporaries depend not only on accomplishment, but also on interactions affected by influence and personality. The historical lore of most fields of scientific endeavor preserve these reputations, often through the identification of founders, innovators, and prolific workers whose contributions are considered fundamental to progress in the field. Historians frequently rely on the historical lore of scientists to guide their studies of the development of ideas, exhibiting justifiable caution in reassessing reputations in the light of current knowledge. However, the transmission of historical lore can obscure the relative importance of accomplishment, influence and personality in shaping contemporary reputations, leaving the historian to either accept reputations at face value or attempt to reconstruct the context in which they were created. The science of taxonomy, because of its rules of priority, leaves a relatively accurate record of historical accomplishment through the persistence of taxa in catalogues and faunal guides. These records allow the modern historian an unbiased means to assess the relative accomplishments of historical figures and therefore a means to critically reassess reputations independent of personality and influence. In the historical lore of North American ichthyology, Louis Agassiz at Harvard and Spencer Baird at the Smithsonian emerge as central figures in the early development of the field during the mid-1800s, contributing not only through the quality and quantity of their science, but also through their roles as institutional leaders and mentors to workers who followed. Charles Girard, originally a student of Agassiz's and later a coworker with Baird, receives little notice in the history of ichthyology, and his reputation is that of a minor player in the initial description of the North American fish fauna, and one whose work appears to have been flawed or even careless when compared to his contemporaries. However, a review of both contemporary and modern taxonomic works reveals that Girard's productivity far exceeded that of either Agassiz or Baird. Furthermore, an examination of the tendency of Girard and his contemporaries to introduce synonymous names into the literature, which might reflect careless or uncritical work, suggests that Girard was among the more accomplished workers of hisera, including Agassiz and Baird. Girard's low ranking in the folklore of North American ichthyology, therefore, can not be attributed to discernible shortcomings in his scientific work, but rather to a public and private campaign of criticism waged by Agassiz after Girard's departure from Harvard. While Agassiz's dispute with Girard stemmed from their personal interactions, he expressed them as criticisms of Girard's work, and thus helped shape Girard's scientific reputation as it has been transmitted through the lore of ichthyology. This case study reveals how scientific reputation may not always rest on accomplishment, but can be influenced by personal interactions obscured by time but nonetheless important to history.
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Geotechnical and geological engineering 17 (1999), S. 335-349 
    ISSN: 1573-1529
    Schlagwort(e): underground gas storage ; pressure barrier ; fibre shotcrete ; stress ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie
    Notizen: Abstract The paper describes an investigation of pressure barriers (plugs) for an underground gas storage facility which were to be constructed from fibre shotcrete. An extensive measurement program on a test plug was carried out to verify the suitability of fibre shotcrete for this purpose. The results of stress and temperature measurements carried out during the construction of the test plug and during cyclic loading of the plug to a water pressure up to 13 MPa are presented. The measurement program provided information on the stress and temperature development inside the plug body during hydration and hardening and also on the residual tensile stresses at the interface between the plug and the rock mass after the end of hydration. Another important output was information on the quality of the plug-rock mass interface, which was critical for a possible leakage. The results obtained during the cyclic loading of the plug revealed uneven stress distribution at the contact and in the adjacent rock mass. It also provided information on the rate of stress redistribution at the contact and inside the rock mass. The results were used to modify the technology of the shotcrete technique to be applied in the final plugs. The gas storage facility using the modified design has been in trial operation since the end of 1998.
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Environmental monitoring and assessment 59 (1999), S. 111-119 
    ISSN: 1573-2959
    Schlagwort(e): adsorbent concentration ; adsorbent size ; adsorption ; chitin ; pH ; reactive dye ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik
    Notizen: Abstract The adsorption of reactive dye on chitin has been investigated with a view to obtain the design data for batch processing of effluents for dye adsorption. The effect of several factors governing the dye adsorption such as the adsorbent concentration, adsorbent size, temperature and pH have been elicited. Desorption of the dye at different temperatures and pH have also been investigated.
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Mycoscience 40 (1999), S. 73-80 
    ISSN: 1618-2545
    Schlagwort(e): Mycena auricoma ; Mycena sect.Radiatae ; Mycena spinosissima ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Two lignicolous species ofMycena (Agaricales, Basidiomycetes) are described and illustrated from eastern, Japan:Mycena auricoma sp. nov., forming ephemeral coprinoid basidiomata and belonging to sectionRadiatae, was found on a dead fallen twig ofQuercus serrata. It appears to close to a Malaysian species,“Trogia” crinipelliformis. Mycena spinosissima in sectionSacchariferae, new to Japan, was collected from dead bark ofAphananthe aspera, a dead fallen inflorescence ofCryptomeria japonica, and a dead fallen twig ofQuercus serrata.
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  • 17
    ISSN: 1618-2545
    Schlagwort(e): cellular slime molds ; dictyostelids ; macrocyst ; mating system ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Macrocyst formation in the sexual cycle was found in three dictyostelid species:Dictyostelium monochasioides, Polysphondylium candidum, andP. pseudo-candidum. Mating tests suggested thatD. monochasioides andP. pseudocandidum were heterothallic andP. candidum was homothallic. The primary walls of macrocysts had partially or fully degenerated, while the inner walls, believed to be tertiary walls, showed an undulate structure.
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Mycoscience 40 (1999), S. 189-191 
    ISSN: 1618-2545
    Schlagwort(e): bamboo fungus ; hyperparasitism ; hyphomycetes ; mycoparasites ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Cryptophiale sphaerospora sp. nov. is described and illustrated based on a single collection attached to a synnematous fungus,Janetia synnematosa, from a dead bamboo culm. It differs from other species ofCryptophiala in having spherical to subspherical conidia and a cerebroid layer of phialides. The overall morohology of this species is smaller than that of previously described species.
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 218 (1999), S. 179-192 
    ISSN: 1615-6110
    Schlagwort(e): Bryophyta ; Mitochondria ; nad5 gene ; group I intron ; molecular phylogeny ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In contrast to animals, the slowly evolving mitochondrial nucleotide sequences of plants appear well suited to investigate phylogenetic relations between old taxonomic groups. Analysis ofnad5 gene sequences in 47 bryophytes, the living representatives of very early land plants, confirm this assessment. Statistically reliable phylogenetic trees are obtained with different mathematical approaches. A group I intron sequence conserved in thenad5 gene of all 30 mosses and 15 liverworts investigated supports a sister group relationship of the two classes. The intron sequence adds phylogenetic information for fine resolution on top of the conserved exon sequences down to the level of classically defined orders or families, respectively. This intron is not present in the hornwortsAnthoceros husnotii andA. punctatus. The results allow statements on diverging taxonomic interpretations and support the monophyly of the liverworts, mosses, Jungermanniidae, Marchantiidae and Bryidae, and allow recognition of subclasses like Hypnanae and Dicrananae. Among the mosses, the derived orders (subclass Bryidae) are confidently set apart from the Sphagnales, Andreaeales, Polytrichales and Tetraphidales with Buxbaumiales occupying a mediating position. Among the liverworts, full support is found for the classic separation of simple (jungermanniid) and complex thalloid (marchantiid) species with a strikingly low mitochondrial sequence divergence among the latter.
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Journal of applied phycology 11 (1999), S. 411-419 
    ISSN: 1573-5176
    Schlagwort(e): Bangiales ; Porphyra life history ; culture ; conchocelis ; conchosporangia ; spores ; neutral conchospores morphology ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Since 1992, as part of a study to circumscribe the genus Porphyra in New Zealand, an extensive culture programme has been developed at the Museum of New Zealand Te Papa Tongarewa. This collection currently houses more than 800 cultures and 150strains. We currently recognise at least 20 species in New Zealand, most of which are undescribed. Close observation of reproduction and the development of conchocelis-phase filaments grown in the laboratory, under controlled conditions of temperature, irradiance and photoperiod, has enabled the recognition of characters that can assist in species separation. The comparative taxonomic value of a range of such characters is discussed, including reporting a novel reproductive mode.
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Journal of applied phycology 11 (1999), S. 429-436 
    ISSN: 1573-5176
    Schlagwort(e): distribution ; harvesting ; Porphyra ; recruitment ; seasonality ; South Africa ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Although Porphyra is commercially farmed in many countries, in South Africa only small harvests of wild populations for sale as nori have been carried out. The discovery that Porphyra improves growth of South African abalone (Haliotis midae) farmed inland-based tanks has led to increased pressure to harvest wild populations. This paper reports on a survey of the distribution and seasonality of Porphyra in the southern Western Cape. Porphyrawas present at all sites surveyed, and showed considerable temporal variation. A significant amount of the Porphyra present is in reserves and therefore protected from harvesting. Close rexamination of one site revealed seasonal populations of Porphyra that occupied different niches dependent on season. Recruitment peaked in spring and autumn, leading to dense summer and winter populations. Summer populations generally grew lower in the eulittoral than winter populations. No pattern in the mortality of larger thalli wasde tected, though sporeling mortality was high following recruitment peaks. Although it seems that most sites in the southern Western Cape are suitable for harvesting, the taxonomy of the genus in the region urgently needs revision if populations are to be appropriately managed.
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  • 22
    Digitale Medien
    Digitale Medien
    Springer
    Mycoscience 40 (1999), S. 165-183 
    ISSN: 1618-2545
    Schlagwort(e): freshwater fungi ; Halosphaeriaceae ; taxonomy ; tropics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The generic concepts inAniptodera, Halosarpheia, Nais andPhaeonectriella are discussed and those species occurring in freshwater are described, some with illustrations. Five new species:Aniptodera lignicola, A. mauritaniensis, A. megalospora, A. palmicola, Phaeonectriella appendiculata are also described. A key to the freshwater species in the above genera and a synoptic diagram of their ascospores are provided.
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Mycoscience 40 (1999), S. 317-320 
    ISSN: 1618-2545
    Schlagwort(e): Ascomycota ; marine fungi ; new species ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A new speciesDactylospora mangrovei is described and illustrated and compared withD. haliotrepha andD. canariensis, all marine inhabiting species.Dactylospora haliotrepha andD. mangrovei are tropical/sub-tropical mangrove species collected in Hong Kong, Malaysia, Taiwan and Thailand, whileD. canariensis was described from temperate waters. A map of the geographical distribution of the three marineDactylospora species is presented.
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  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Mycoscience 40 (1999), S. 185-188 
    ISSN: 1618-2545
    Schlagwort(e): Amphisphaeria ; ascomycetes ; bamboo fungi ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A new species ofArecophila and a species previously known asAmphisphaeria coronata are described and illustrated from dead culms of bamboo.Arecophila bambusae sp. nov. is distinct in the genus in having ellipsoidal ascospores with slightly round ends, and asci with a narrow subapical ring.Arecophila coronata comb. nov. has asci with a wedgeshaped apical ring and weakly striated ascospores enclosed in wide mucilaginous sheath.
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  • 25
    ISSN: 1573-5125
    Schlagwort(e): irradiance ; nitrogen uptake ; phytoplankton ; Tagus estuary ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effect of light, temperature and ammonium on inorganic nitrogen uptake by phytoplankton was investigated from June 1994 through December 1995 at three sites in the Tagus estuary (Portugal), during high tide of neap tides. Ammonium concentrations higher than 10 μM reduced nitrate uptake down to 24% but never prevented it. Below this threshold concentration, nitrate uptake was neither inhibited nor changed. Uptake of both nitrate and ammonium as a function of light intensity exhibited a saturation response. Uptake reduction occurred in the near bottom phytoplankton populations, particularly for nitrate. The ammonium uptake system was less limited by light than the nitrate uptake system, indicating the importance of ammonium as a nitrogen source for the phytoplankton which is likely to experience high changes in light in the well-mixed water column of this estuarine environment. Ammonium uptake was exponentially related to temperature in the upper estuary whereas in the mid and lower estuary this relationship was linear. The effect of temperature on nitrate uptake was linear but far less marked than for ammonium uptake.
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  • 26
    ISSN: 1573-143X
    Schlagwort(e): alevin ; Atlantic salmon (Salmo salar) ; development ; egg ; temperature ; thermal tolerance ; yolk
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Three embryonic stages of Atlantic salmon (Salmo salar L.) were subjected to eight constant incubation temperatures (4, 7, 10, 12, 14, 16, 19 and 22 °C) exceeding the range usually experienced in natural conditions. A change in thermal tolerance during the embryonic and larval development was registered: pre-hatching stages showed an upper thermal limit at about 16 °C, while hatched larvae survived until 22 °C. Temperature significantly affects developmental rate, resulting in a faster development and, consequently, lower yolk weight percentage at higher temperatures. We found positive relationships between incubation temperature and body size (length and weight) in the less developed stages, in which some yolk remained, but size decreased at increasing temperatures when yolk was completely exhausted.
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  • 27
    ISSN: 1573-143X
    Schlagwort(e): cyanobacteria ; microalgae ; Spirulina ; Spirulina composition ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The influence of temperature on growth and biomass composition of two species of Spirulina, S. maxima and S. platensis used for food was studied. A 4L fermenter with temperature and agitation control was used to cultivate both species. Under continuous light, maximum cell production of 2.4 g l−1 was verified for both cultures studied at temperatures above 25 °C: S. maxima (30 °C and 35 °C) and S. platensis (25 °C and 30 °C). An accentuated lag phase was observed for all cultures at lower temperatures (15–20 °C), and a maximum biomass production of 1.5 g l−1 was achieved. It was also observed that an increase of temperature caused a marked decrease in protein content, while carbohydrate synthesis was stimulated. The concentration of γ-linolenic acid varied from 11–16% for S. maxima and from 12–14% for S. platensis, at the optimum growth temperatures. Greater culture volumes were also studied in order to compare the performance of glass and plastic containers. At optimum growth temperature, S. maxima produced the same cell growth and similar final biomass composition.
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    European journal of plant pathology 105 (1999), S. 509-512 
    ISSN: 1573-8469
    Schlagwort(e): tospovirus ; resistance ; Capsicum sp. ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Infection by two isolates of impatiens necrotic spot tospovirus (INSV) under temperature regimes of 25/18°C (day/night) or 33°C (continuous) was studied in Capsicum annuum (systemically susceptible to tomato spotted wilt tospovirus, TSWV), C. chinense PI 152225 and PI 159236 (reacting hypersensitively to TSWV) and Nicotiana benthamiana (systemically susceptible to both tospoviruses). At 25/18°C infection was systemic in all hosts tested. At 33°C infection in N. benthamiana was systemic whereas in C. annuum and C. chinense it was restricted to the inoculated leaves. The result differed from that reported for TSWV, where high temperature made plants more susceptible, or caused no difference. Exchanging temperature regimes 6 h to 4 days after inoculation did not affect the final results one month later, with plants being only locally infected at 33°C continuous regime, or systemically infected at 25/18°C alternate regime. The two INSV isolates were biologically and serologically stable for 5 passages in N. benthamiana held continuously at 33°C.
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Journal of systems integration 9 (1999), S. 167-185 
    ISSN: 1573-8787
    Schlagwort(e): flexibility ; complexity ; systems approach ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik
    Notizen: Abstract In this paper we present a taxonomy of manufacturing problems, labeled in a general sense as Design, Production, or Distribution problems. One or more basic systems concepts, such as complexity and adaptation, attach themselves to each such problems. By combining the hierarchical Design—Production—Distribution idea with system concepts, we establish the fact that there is, indeed, a significant systems component to most problems of modern manufacturing.
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 214 (1999), S. 91-102 
    ISSN: 1615-6110
    Schlagwort(e): Asteraceae ; Lactuceae ; Aetheorhiza ; Launaea ; Reichardia ; Sonchus ; Pollen ; taxonomy ; harmomegathy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The pollen morphology of the taxa belonging to the generaAetheorhiza Cass.,Launaea Cass.,Reichardia Roth andSonchus L. in the Iberian Peninsula has been studied with light and electron microscopy. The pollen is 3(-4)-zonocolporate and echinolophate (without polar lacunae, but in general with prelacunae), with equatorial ridges and 15–20 lacunae: 3–4 poral, 6–8 abporal and 6–8 paraporal. Small to medium size, P × E = 19−36 × 23–42 µm; sometimes two different sizes have been found. Exine 3–9 µm thick and ornamentation microreticulate and echinate. The results clearly show the relationships between genera.
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  • 31
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 214 (1999), S. 161-186 
    ISSN: 1615-6110
    Schlagwort(e): Rubiaceae ; Rubioideae ; Angiosperms ; cladistics ; DNA sequences ; phylogeny ; rps16 intron ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The phylogeny of the subfamilyRubioideae (Rubiaceae) was estimated from sequence variation in therps16 intron (cpDNA) in 143 ingroup and 5 outgroup taxa. The analysis largely confirms a recent one based onrbcL sequences, but branch support is often much stronger. Three of the traditional subfamilies are supported,Rubioideae, Cinchonoideae s. str., andIxoroideae s. l. while there is no support forAntirheoideae. TheRubioideae are the sister group of all otherRubiaceae and comprise the tribesAnthospermeae, Coccocypseleae, Cruckshanksieae, Coussareeae, Gaertnereae, Hedyotideae, Knoxieae, Morindeae, Ophiorrhizeae, Paederieae, Pauridiantheae, Perameae, Psychotrieae, Rubieae, Spermacoceae, Theligoneae, andUrophylleae. TheHamelieae andHillieae belong to theCinchonoideae. Rachicallis andSiemensia should be transferred from theHedyotideae to theCinchonoideae. ThePauridiantheae, Urophylleae, Ophiorrhizeae, andRaritebe form the basalmost subclade of theRubioideae. The second basalmost clade consists of the generaLasianthus andPerama. The third basalmost clade consists of the tribesCoussareeae, Coccocypseleae andCruckshanksieae, and the generaDeclieuxia andHindsia. The tribesKnoxieae, Anthospermeae, Argostemmateae, Paederieae, Theligoneae, Rubieae, Hedyotideae, andSpermacoceae are members of one clade. TheKnoxieae are monophyletic ifOtiophora, Otomeria, andPentas are included. The tribeAnthospermeae is supported as monophyletic, but its subtribes are not. ThePaederieae, together withTheligonum, form a paraphyletic grade basal to theRubieae. TheHedyotideae, includingSchismatoclada, form a grade at the base of theSpermacoceae. TheGaertnereae are monophyletic and distinct from thePsychotrieae. TheMorindeae are monophyletic and includeDamnacanthus andMitchella. Schradera is the sister group of theMorindeae. ThePsychotrieae are monophyletic when theGaertnereae, Lasianthus, andDeclieuxia are excluded. The recognition of a subtribeHydnophytineae leaves the rest of thePsychotrieae paraphyletic.Psychotria is paraphyletic with respect to all other genera of the tribe. Approximately 50 genera are here classified for the first time based on molecular data.
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 219 (1999), S. 199-208 
    ISSN: 1615-6110
    Schlagwort(e): Brexioideae ; Brexia ; Ixerba ; Roussea ; Saxifragaceae s. l. ; 18S rDNA andrbcL sequence analysis ; molecular systematics ; phylogenetic analysis ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Previous molecular phylogenetic analyses have demonstrated that Saxifragaceae sensu lato are polyphyletic, with component lineages scattered throughout the eudicots. As part of our effort to elucidate the relationships of members of Engler and Prantl's Saxifragaceae s. l., we undertook a molecular systematic study of subfamily Brexioideae, which comprises three genera:Brexia, Ixerba, andRoussea. Not all taxonomic treatments have concurred, however, in placing these genera together. To elucidate relationships among these three genera as well as their relationships to other angiosperms we constructed large data sets ofrbcL, 18S rDNA, andrbcL + 18S rDNA sequences. Our phylogenetic analyses indicate clearly that Brexioideae are polyphyletic.Brexia is part of a celastroid clade that also includesParnassia, Lepuropetalon, and Celastraceae.Ixerba appears as sister to a large eurosid I clade;Roussea appears as part of Asterales. Molecular data, therefore, indicate that Brexioideae are a polyphyletic assemblage and component genera should ultimately be incorporated into other groups. Our studies continue to demonstrate the polyphyly not only Saxifragaceae s. l., but also of its constituent subfamilies.
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  • 33
    ISSN: 1573-5028
    Schlagwort(e): amylose ; splicing ; starch synthase ; temperature ; waxy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Granule-bound starch synthase (GBSS), a product of the waxy gene in rice (Oryza sativa L.), is necessary for the synthesis of amylose in the endosperm. In an extended pedigree of 89 rice cultivars, we have previously shown that all cultivars with more than 18% amylose had the sequence AGGTATA at the leader intron 5′ splice site, while all cultivars with a lower proportion of amylose had the sequence AGTTATA. This single-nucleotide polymorphism reduces the efficiency of GBSS pre-mRNA processing. It also results in alternate splicing at multiple sites, some of which have non-consensus sequences. Here we demonstrate that this same G-to-T polymorphism is also associated with differential sensitivity to temperature during the period of grain development. Cultivars with the sequence AGTTATA have a substantial increase in accumulation of mature GBSS transcripts at 18 °C compared to 25 or 32 °C. The selection of leader intron 5′ splice sites is also affected by temperature in these cultivars. A 5′ splice site −93 upstream from that used in high-amylose varieties predominates at 18 °C. At higher temperatures there is increased utilization of a 5′ splice site at −1 and a non-consensus site at +1. Potential implications of differential 5′ splice site selection and associated differences in 3′ splice site selection on transcript stability and translational efficiency are discussed.
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  • 34
    ISSN: 1573-5060
    Schlagwort(e): Pisum sativum L. ; frost resistance ; floral initiation ; photoperiod ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Frost is one of the main climatic stresses which has to be overcome by a winter pea crop. Some forage lines show a delayed floral initiation, which helps them to escape the main winter freezing periods, as a higher susceptibility to frost is observed after floral initiation commences. Frost tolerant forage peas have been used in all winter pea breeding programs in France and our main purpose was to evaluate to what extent those lines and the current winter varieties are variable for the date of floral initiation in field conditions. A field experiment was carried out during two years at the INRA experimental station of Mons (northern France). Different genotypes (9 in 1995–1996 and 12 in 1996–1997) were sown at approximately monthly intervals between September and June to provide a range of photothermal conditions. The date of floral initiation was determined by destructive sampling. We observed variability for the date of floral initiation among the different genotypes and sowing dates. Our data particularly highlighted the different reactions to photoperiod. Three varieties had no detectable reaction. Six varieties exhibited a quantitative response, with varied intensities. Lastly, the three forage varieties showed a qualitative, high response to photoperiod, which indicated the presence of the Hr allele, already described in Pisum.
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  • 35
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 214 (1999), S. 133-140 
    ISSN: 1573-5036
    Schlagwort(e): ammonium ; eucalyptus ; nitrate ; pH ; root uptake ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Ammonium and nitrate uptake by roots of Eucalyptus nitens was characterised with respect to pH and temperature. Uptake of ammonium and nitrate was measured as depletion from solutions by roots of intact 11 week old solution-cultured seedlings. Uptake rates of ammonium were consistently higher than those of nitrate in all experiments. Uptake rates for ammonium were 200% higher at pH 4 than at pH 6, but for nitrate were unchanged. Uptake rates of ammonium and nitrate were both reduced to a similar extent (70%) with a decrease in temperature from 20 °C to 10 °C. For ammonium uptake, there was rapid (〈24 hr) adaptation to a reduction in root temperature. The apparent preference shown here for ammonium over nitrate could be indicative of E. nitens growing in cold, acidic forest soils where ammonium is commonly more available than nitrate. These results suggest that N uptake rates of E. nitens may be maximised under a wide variety of conditions if N is supplied predominantly in the ammonium form.
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  • 36
    Digitale Medien
    Digitale Medien
    Springer
    Genetic resources and crop evolution 46 (1999), S. 143-147 
    ISSN: 1573-5109
    Schlagwort(e): Amygdalus ; distribution ; domestication ; taxonomy ; wild relatives
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Almond, Amygdalus communis L., is an ancient crop of south west Asia. Selection of the sweet type marks the beginning of almond domestication. Wild almonds are bitter and eating even a relatively small number of nuts can be fatal. How man selected the sweet type remains a riddle. Also, the wild ancestor of almond has not been properly identified among the many wild almond species. Breeding experiment, which is the most critical test for identifying the wild progenitors of other crops, is ineffective in almond, because it is interfertile with many wild taxa. The so-called wild A. communis of central Asia cannot be regarded as a genuine wild form, but as a feral form, or remains of old afforestation. The wild taxa morphologically akin to almond, A. korshinskyi (H.-M.) Bomm. and A. webbii Spach, are also feral types occurring in the Middle East and southern Europe, respectively. The taxon A. fenzliana (Fritsch) Lipsky is the most likely wild ancestor of almond for three reasons: 1. It is a genuine wild type forming extensive thickets of large trees young seedlings and all the intergradations between them in nature; 2. Its morphology, and particularly the partially pitted grooved nut-shell are within the range of variation of almond, and 3. A. fenzliana is native of Armenia and western Azerbaijan in the Middle East where almond was apparently domesticated.
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  • 37
    ISSN: 1573-5109
    Schlagwort(e): evolution ; genetic resources ; PCR-RFLP ; RAPDs ; Vicia ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract We report the results of two methods of DNA analysis to elucidate phylogenetic relationships among 29 Vicia subgen. Vicia species in comparison with two species of subgenus Vicilla sect. Vicilla. The methods employed were RAPD analysis of total genomic DNA and PCR-RFLP analysis of five chloroplast genes, rbcL, rpoB, 16S, psaA and trnK. The results of each method were similar and complementary, and support the current taxonomic systems of subsp. Vicia. According to RAPD and PCR-RFLP analysis the Narbonensis complex can be considered a well separated section, which may be related to section Vicia. Sections Vicia, Atossa and Wiggersia are separate, but closely related sections. Species of the section Hypechusa form a single monophyletic section, where V. lutea, V. anatolica and V. hyrcanica are quite remote from other species. Our results suggest that within the subgenus Vicia, V. faba is more closely related to V. bithynica and that these two species are most closely related to section Peregrinae. We found that PCR-RFLP of cp DNA provided more precise information concerning relationships between Vicia sections than RAPD analysis. However, RAPD analysis was more informative concerning diversity of closely related Vicia taxa, such as the variable groups, section Narbonensis and V. sativa aggregate.
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Genetic resources and crop evolution 46 (1999), S. 207-211 
    ISSN: 1573-5109
    Schlagwort(e): introduced species ; karyotypes ; taxonomy ; Vicia sativa agg
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract V. sativa L. sensu strictu was introduced in Rio Grande do Sul (Southern Brazil) by Italian settlers and is nowadays cultivated for forage in backyards and fields. V. angustifolia L. is a widespread highly polymorphic naturalized ruderal. Both taxa grow sympatrically and morphologically transitional types are often found. We analyzed 37 accessions of V. sativa, V. angustifolia, intermediate types, and V. cordata Wulf. ex. Hoppe from Rio Grande do Sul, for karyotypes, corolla and legume color, seed color pattern, pod constrictions and phenological development. Karyotypes allowed a clear distinction between the taxa: V. sativa (2n=12) had a metacentric marker chromosome, V. angustifolia and intermediate types (2n=12) only acrocentric chromosomes and V. cordata presented 2n=10. Flowering and fruiting periods were shorter for V. sativa than for V. angustifolia, which was separated into early and late flowering groups. Qualitative characters separated the taxa by Jaccard coefficients into three groups: V. sativa at 0.5 similarity level, V. angustifolia and intermediate types at 0.6 and V. cordata joined V. sativa at 0.12. Our results show that karyotypes and a range of qualitative characters are diagnostic for the aggregate represented in Southern Brazil.
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  • 39
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 403 (1999), S. 27-38 
    ISSN: 1573-5117
    Schlagwort(e): Cladocera ; Daphnia ; taxonomy ; homonymy ; phylogenetic relationships ; Patagonia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Daphnia sarsi Daday, 1902 is redescribed from Patagonian populations and type material. Its taxonomic and nomenclatorial status is discussed. Because of the homonymy with D. sarsi Schödler, 1877, assigned to Australian populations, D. dadayana is proposed as new name. It is concluded that D. dadayana is a valid species with several morphological peculiarities and the proposed synonymies with D. carinata and D. similis can not be supported. Its subgeneric position is intermediate between Daphnia s. str. and Ctenodaphnia and there is an ontogenetical shift of the dorsocephalic suture from Ctenodaphnia-like to Daphnia-like. The possible origin of the group of species assigned to the subgenus Daphnia from a Ctenodaphnia-like ancestor is suggested.
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  • 40
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 403 (1999), S. 97-107 
    ISSN: 1573-5117
    Schlagwort(e): Algal growth rate ; salinity ; temperature ; pH ; Nannochloropsis ; Tetraselmis ; Isochrysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The possibility of improving the growth rate of different high-quality marine algae was studied. Optimum culture conditions relative to salinities, temperatures and pH levels were defined for three species of Nannochloropsis, Tetraselmis and Isochrysis. In Nannochloropsis, the optimum production ranges were as follows: 20–40‰, 19–21 °C, without using CO2. The optimum conditions for Tetraselmis were: 20–35‰, 19–21 °C, without using CO2. For Isochrysis, the optimum conditions were: 25–35‰, 24–26 °C, also without using CO2.
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  • 41
    ISSN: 1573-5117
    Schlagwort(e): taxonomy ; marine nematodes ; Sabatieria ; the Strait of Magellan ; Chile
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Eight species of the genus Sabatieria, one of which is new to science, are described from the Strait of Magellan and the Beagle Channel, Chile. Sabatieria coomansi n. sp. is characterised by a rather long body (3236–4012 μm) with conspicuous lateral differentiation; head diameter 24 μm, amphids 2.25 turns; long spicules (132–149 μm) or 1.6–1.9 abd, 23–26 precloacal supplements, tail 3.3–3.6 abd. This species belongs to the praedatrix group (Platt, 1985). Sabatieria arcuata is found since its original description by Wieser in 1954. Six other species, i.e., S. celtica Southern, 1914, S. falcifera Wieser, 1954, S. furcillata Wieser, 1954, S. granifer Wieser, 1954, S. mortenseni (Ditlevsen, 1921) and S. parabyssalis Wieser, 1954 are redescribed in detail with emphasis on new or shortly described morphological features.
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 408-409 (1999), S. 175-183 
    ISSN: 1573-5117
    Schlagwort(e): internal loading ; iron ; oxic ; anoxic ; temperature ; macrophyte
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The release of phosphorus (P) and iron (Fe) was studied in undisturbed sediment cores from littoral and profundal sediments of shallow, eutrophic Lake Arreskov (Denmark). The cores were incubated for 100 days in darkness under oxic and anoxic conditions at 12 and 19 °C and cumulative fluxes of P and Fe were determined. The littoral sediment showed higher P release than the profundal sediment under both oxic and anoxic conditions, however, the difference was only significant during the first 35 days under anoxic conditions. The release rates of P and Fe were significantly higher under anoxic than under oxic conditions. Sequential extractions of P-fractions in sediment from different depths (0–15 cm) were conducted before and after the experiment. Under anoxic conditions, iron-bound P was the most important fraction for the loss of P from both sediments. The decrease in the iron-bound P pool contributed 54% and 86 % of the loss of total particulate P (TPsed) from littoral and profundal sediments under anoxic conditions, respectively, whereas it under oxic conditions only constituted 25% of the TPsedlost from the littoral sediment. Organic P accounted for 31 and 55% of the TPsedlost from the littoral sediment under anoxic and oxic conditions, respectively, while organic P was unimportant (〈 1%) for the loss of TPsedfrom the profundal sediment under anoxic conditions. This indicates that littoral sediments may contribute significantly to the internal P loading, especially if low O2concentrations occur at the sediment–water interface.
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  • 43
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 416 (1999), S. 97-106 
    ISSN: 1573-5117
    Schlagwort(e): Oreochromis niloticusL. ; Lake Langeno ; diet ; algal-detritus ; chemical nutrients ; assimilation efficiency ; condition factor ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The composition, nutrient content and digestibility of the diet of Oreochromis niloticus were studied based on stomach and rectal samples collected monthly between December, 1995, and December, 1996, from Lake Langeno. The diet of O. niloticus was composed of a mixture of algal-based detritus, macrophyte scraps, phytoplankton and silt. Inorganic silt, macrophytes and detritus were more dominant in the diet during the wet than in the dry season. Total organic matter (TOM) in the diet was generally low (413 mg g-1 d.w.) reflecting the high proportion of inorganic silt in all seasons. Carbohydrates, proteins and lipids were important nutrients and constituted on average about 139, 185 and 57 mg g-1 d.w., respectively. The levels of all these nutrients varied significantly (ANOVA, P〈0.0001) between months and declined during the wet season. Variation was observed in the ability of the fish to digest and absorb the different components of the food. Protein (41%) was better assimilated than total organic matter (32.7%), carbohydrate (31.7) or lipids (29.8%). The quality of the food expressed as P:E ratio (18.6-28.8 mg KJ-1) ranged from inadequate to adequate. The condition factor (CF) of the fish varied significantly between months in males (ANOVA, F=12.99, p〈0.0001) and females (ANOVA, F=14.46, p〈0.0001). It is concluded that the relatively poor condition factor (CF= 1.67) of O. niloticus in Lake Langeno, compared with other Rift Valley Lakes, follows from the low organic matter content and high proportion of inorganic silt in the diet.
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  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 400 (1999), S. 85-114 
    ISSN: 1573-5117
    Schlagwort(e): morphology ; clone ; temperature ; salinity ; parthenogenesis ; sexual reproduction ; cluster genotype ; general purpose genotype ; clonal taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Limnocythere inopinata (Baird) is a Holarctic species, widely distributed in non-marine waters, and mainly occurring in unisexual populations. It displays polymorphic traits which could be useful for taxonomical and (palaeo)ecological purposes, if the origin of these traits could be better understood. Three clones of L. inopinata were cultured in the laboratory under various temperature and salinity conditions (i.e. temperature 15, 20 and 25 °C, salinity expressed as electrical conductivity 400, 2000, 5000 and 8000 μS cm−1). Morphological traits for both the valves (shape and size) and soft parts (11 limb setae) were observed. Field populations from Chinese salt lakes and from Austrian lakes were also compared. The freshwater population from Mondsee and its derived clone M develop larger valves than those of the other two clones, clone N (from Neusiedlersee) and clone S (from Seewinkel, Oberer Stinkersee), which live exclusively in saline (alkaline) water. Parthenogenetic specimens from the freshwater lake Mondsee and sexually reproducing females from the Chinese salt lakes both have sub-rectangular valves with straight dorsal margin; the saline clones and populations have highly arched valves with rounded dorsal margin. No direct effects of temperature or salinity on valve ornamentation (reticulation, nodation) have been found. At least for nodation, a genetic factor seems apparent, as the saline clones N and S are never nodose, while the freshwater animals from Mondsee and the sexual animals from the Chinese salt lakes can be both with or without nodes. In the former case, number and position of nodes are variable. Both absolute and relative length of limb setae can be affected by environmental factors and by genotype, and this is the first time that this has been demonstrated in non-marine ostracods. Based on the present observations and experiments, it is concluded that L. inopinata is a variable, polymorphic species, consisting of a (semi-) continuous morphological cluster, in which both clonal genotypes and sexual haplotypes are nested. Therefore, Limnocythere sappaensis Staplin and L. binoda Huang are considered synonyms of L. inopinata; L. mongolica Daday is a possible synonym; L. sanctipatricii sensu Huang and L. dubiosa sensu Huang from Lake Qinghai are most likely erroneous identifications. Apparently recognisable clones with typical ecologies cannot be allocated a taxonomic rank, as this does not reflect a phylogenetic reality. Such links between recognisable morphologies and typical ecological ranges are useful for palaeoenvironmental reconstructions, but are applicable at a regional scale only.
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  • 45
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 400 (1999), S. 129-140 
    ISSN: 1573-5117
    Schlagwort(e): fish ; energetics ; temperature ; feeding ; prey abundance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract I examined food consumption and growth of walleye larvae in extensive culture ponds using direct methods and a bioenergetics model, and compared my results with laboratory feeding and growth studies. Walleye showed a diel pattern of increasing gut fullness during daylight hours. Larvae exhibited lower maximum food consumption rates in the ponds than predicted from previous short-term laboratory feeding studies. Direct estimates and bioenergetics model estimates of daily food consumption in the culture ponds were in poor agreement and the discrepancy varied with respect to walleye size. Food consumption rates in the ponds were related to walleye size (direct estimates) or water temperature (bioenergetics model estimates) but not zooplankton abundance. Growth exceeded 0.10 g g−1 d−1 for all but one sampling interval and the maximum growth rate in the culture pond fish was double the maximum growth rate determined in the laboratory. Growth was positively related to pond temperature and negatively related to walleye mass, but was not significantly related to zooplankton abundance. Gross conversion efficiency was negatively related to walleye mass, positively related to zooplankton abundance and not related to temperature. Food consumption and growth of walleye larvae in the field may be food-limited at much lower prey abundances than previous laboratory research has suggested.
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  • 46
    Digitale Medien
    Digitale Medien
    Springer
    Environmental biology of fishes 55 (1999), S. 307-319 
    ISSN: 1573-5133
    Schlagwort(e): embryo survival ; dissolved organic carbon ; DOC ; nest depth distribution ; development times ; temperature ; underwater UVR environments
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We examined the effect of UVR on the success of early life history stages of Lepomis macrochirus in two lakes with contrasting underwater UVR environments. We tested the prediction that when exposed to similar amounts of UVR, bluegill embryos from lakes with high UVR environments have lower mortality than those from lakes with low UVR. We measured embryo survival in the two lakes by performing three experiments in which ambient UVR was manipulated. Embryos responded similarly to UVR exposure regardless of the lake of origin. However, UV-B in UVR transparent lakes is a potentially important factor in the success of early life history stages of the bluegill. A survey of the natural nesting depths in the two lakes revealed that the median depth at which bluegills construct their nests was greater in Lake Giles (high underwater UVR environment) than in Lake Lacawac (low underwater UVR environment).
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  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 405 (1999), S. 179-188 
    ISSN: 1573-5117
    Schlagwort(e): bivalve ; surf clam ; oxygen uptake ; clearance rate ; temperature ; body size
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Oxygen uptake and feeding (clearance) rates were measured for the tuatua Pahpies donacina from an exposed sand beach characterised by variable levels of productivity (4–12 μg l−1chlorophyll a) and an annual temperature range between 8 and 19 °C. The aims of the study were to assess the ability of the surf clam to regulate feeding activity and oxygen uptake over a range of food concentrations and temperature conditions. Tuatuas, shell length 27–95 mm, were exposed to temperatures of 10, 15 and 20 °C in summer and 5, 10 and 15 °C in winter. Aquatic oxygen uptake depended on both body weight and exposure temperature with body weight explaining the majority of the variation in the multiple-regression equation. Weight specific oxygen uptake was similar at the two upper temperatures and significantly reduced at the lower temperature. For a standard length tuatua the oxygen uptake was similar at 10 °C in both summer and winter. Clearance rates of P. donacina feeding on laboratory cultures of Isochrysis galbana were low compared with other bivalves. They increased logarithmically with cell concentration up to a maximal rate, then declined at higher cell levels. The clearance rate depended upon shell length and dry tissue weight and was higher for tuatua acclimated at 10 °C than at 15 °C. It was concluded that P. donacina shows seasonal adjustment in oxygen uptake and filtration rate to compensate for seasonal temperature variation in the habitat. The 10 °C temperature optima for the clearance rate is consistent with the southern distribution of this species allowing it to feed effectively during periods of high food availability.
    Materialart: Digitale Medien
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  • 48
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 400 (1999), S. 85-114 
    ISSN: 1573-5117
    Schlagwort(e): morphology ; clone ; temperature ; salinity ; parthenogenesis ; sexual reproduction ; cluster genotype ; general purpose genotype ; clonal taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Limnocythere inopinata (Baird) is a Holarctic species, widely distributed in non-marine waters, and mainly occurring in unisexual populations. It displays polymorphic traits which could be useful for taxonomical and (palaeo)ecological purposes, if the origin of these traits could be better understood. Three clones of L. inopinata were cultured in the laboratory under various temperature and salinity conditions (i.e. temperature 15, 20 and 25 °C, salinity expressed as electrical conductivity 400, 2000, 5000 and 8000 μS cm−1). Morphological traits for both the valves (shape and size) and soft parts (11 limb setae) were observed. Field populations from Chinese salt lakes and from Austrian lakes were also compared. The freshwater population from Mondsee and its derived clone M develop larger valves than those of the other two clones, clone N (from Neusiedlersee) and clone S (from Seewinkel, Oberer Stinkersee), which live exclusively in saline (alkaline) water. Parthenogenetic specimens from the freshwater lake Mondsee and sexually reproducing females from the Chinese salt lakes both have sub-rectangular valves with straight dorsal margin; the saline clones and populations have highly arched valves with rounded dorsal margin. No direct effects of temperature or salinity on valve ornamentation (reticulation, nodation) have been found. At least for nodation, a genetic factor seems apparent, as the saline clones N and S are never nodose, while the freshwater animals from Mondsee and the sexual animals from the Chinese salt lakes can be both with or without nodes. In the former case, number and position of nodes are variable. Both absolute and relative length of limb setae can be affected by environmental factors and by genotype, and this is the first time that this has been demonstrated in non-marine ostracods. Based on the present observations and experiments, it is concluded that L. inopinata is a variable, polymorphic species, consisting of a (semi-) continuous morphological cluster, in which both clonal genotypes and sexual haplotypes are nested. Therefore, Limnocythere sappaensis Staplin and L. binoda Huang are considered synonyms of L. inopinata; L. mongolica Daday is a possible synonym; L. sanctipatricii sensu Huang and L. dubiosa sensu Huang from Lake Qinghai are most likely erroneous identifications. Apparently recognisable clones with typical ecologies cannot be allocated a taxonomic rank, as this does not reflect a phylogenetic reality. Such links between recognisable morphologies and typical ecological ranges are useful for palaeoenvironmental reconstructions, but are applicable at a regional scale only.
    Materialart: Digitale Medien
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  • 49
    ISSN: 1573-5117
    Schlagwort(e): plankton patches ; bioluminescence ; temperature ; Ionian and Black Seas
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Small-scale heterogeneity of bioluminescence intensity was studied in offshore regions of the Black and Ionian Seas in September/October, 1989. Bathyphotometric casts were deployed every 3 min over a period of several hours from a drifting vessel. Casts were accompanied by temperature profiles and zooplankton sampling. Taking into account the vessel drift, the sampling interval was equal to a spatial resolution from 15 to 25 m. Measurements were carried out during the day and night periods. From adaptive spectral analysis it was shown that the horizontal dimensions of the bioluminescent heterogeneities were between 75 and 1500 m in the Black Sea and 89–800 m in the Ionian Sea. The horizontal dimensions of the heterogeneities were 85–818 m and 85–500 m for zooplankton biomass and 80–1800 m and 85–600 m for the temperature field in the Black and Ionian Seas, respectively. Therefore, it is assumed that physical and dynamical factors dominate in the formation of small-scale spatial heterogeneity of the studied fields. Biological factors, such as diel vertical migrations, trophic interactions etc. will also contribute to the formation of patches at night.
    Materialart: Digitale Medien
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  • 50
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 394 (1999), S. 145-152 
    ISSN: 1573-5117
    Schlagwort(e): Heliodiaptomus ; H. elegans ; redescription ; synonymy ; H. serratus ; taxonomy ; Copepoda ; Calanoida
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Heliodiaptomus elegans Kiefer, 1935, incompletely described from Myanmar, is redescribed on specimens from Thailand. A Chinese congener, H. serratus Shen & Tai, 1962, is sunk into the synonymy of H. elegans.
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  • 51
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 397 (1999), S. 21-28 
    ISSN: 1573-5117
    Schlagwort(e): Turbellaria ; taxonomy ; morphology ; Extremadura ; Spain
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Three new species of Rhabdocoela belonging to the Families Dalyellidae: Microdalyellia bipennata, and Typhloplanidae: Mesocastrada iberiensis, and Mesostoma extremeniensis are described. Fourteen species of the Orders Catenulida, Macrostomida, Proseriata and Rhabdocoela are cited the first time for Extremadura (southwest Spain).
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  • 52
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 412 (1999), S. 25-34 
    ISSN: 1573-5117
    Schlagwort(e): Chirocephalus ; Anostraca ; taxonomy ; ecology ; Slovenia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Numerous specimens of Chirocephaluswere found repeatedly over the last eight years in an intermittent lake in SW Slovenia. They were first identified as Chirocephalus spinicaudatusSimon, 1886. Later it turned out that they fit the diagnosis of Chirocephalus croaticus (Steuer, 1899), a species described from a small lake in Southern Croatia, about 300 km from Slovenia. It was considered as endemic of its type locality only. Now its range expands into NW direction. The population in Slovenia is in good condition and, if there is no change in land use, could persist for a long time. A small population of the same species in a small puddle near the intermittent lake Cerkniško Jezero (about 30 km from lake Petelinjsko Jezero) was destroyed a few years ago. A detailed description of specimens of both sexes is given and some information on their ecology is added. Particular attention is given to the male legs which could provide good diagnostic characters. For comparison, legs of Chirocephalus diaphanus Prévost, 1803 are shown.
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  • 53
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 412 (1999), S. 143-153 
    ISSN: 1573-5117
    Schlagwort(e): Cletocamptus merbokensis ; Harpacticoida ; taxonomy ; Malaysia ; mangroves
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Cletocamptus merbokensis sp. nov. is described from material collected out of muddy sediments in the Merbok mangrove forest, northwest peninsula Malaysia. It is distinguished from all other known species of Cletocamptus by the presence of only two setae on P2 and P3 endopod-2 and no inner seta on P4 exopod-2; and by the form of the male P5 in which the baseoendopod and most of the endopodal and exopodal lobes are absorbed into the somatic cuticle. The higher taxonomic position of the genus is briefly discussed.
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  • 54
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 412 (1999), S. 155-164 
    ISSN: 1573-5117
    Schlagwort(e): zooplankton ; ecology ; lakes ; Mysis relicta ; food webs ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The opossum shrimp (Mysis relicta) is a holarctic planktivore that undergoes diel vertical migration (DVM), ascending at night from deeper water or the lake bottom into the upper water column to feed. In deep lakes that thermally stratify, M. relicta spends most of the time on or near the lake bottom in cold water where food resources are low; but, M. relicta migrates daily into warmer layers to feed where food resources are more abundant. Hence, in deep lakes M. relicta traverses steep temperature and prey density gradients while migrating through the water column to forage. We conducted a laboratory growth experiment of factorial design that simulated the range of temperatures and densities of natural zooplankton forage encountered by M. relicta during DVM. Somatic growth, measured as change in total length and lipid-free biomass, was not significantly different among experimental treatments. Analysis of variance showed that M. relicta stored energy in the form of lipid instead of using the energy mainly to drive increased somatic growth, but only at the colder temperatures. Lipid storage was 24% (± 4.3 sd) in 4 °C-high forage treatment compared to 6% (± 1.1) at 14 °C-high forage treatment. Energy conversion efficiency (ECE) of M. relicta was highest (21.3% ± 5.8) at 4 °C and lowest (3.3% ± 0.9) at 14 °C, regardless of prey density. The experiment showed that Mysis relicta feeds at high food densities where ECE is low, but spends most of the time in colder water where ECE is high. These results support McLaren's metabolic efficiency hypothesis, which predicts that feeding in the more productive surface waters and then migrating to colder waters is reproductively advantageous. Moreover, owing to high metabolic efficiency in the coldest waters and rapid DVM, M. relicta is able to sequester much of the epilimnetic zooplankton production near or on the lake bottom, thereby forcing the lake food web toward a configuration dominated by mysids, benthic or deepwater fishes and small, agile zooplankton.
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  • 55
    ISSN: 1573-5117
    Schlagwort(e): mangrove ; regeneration ; reforestation ; salinity ; seedlings ; temperature ; water supply
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In the Ciénaga Grande de Santa Marta, a brackish lagoon system on the Caribbean coast of Colombia, human-induced changes in the hydrological system caused hypersalinisation of the soils. As a result, 30 000 ha of originally 51 000 ha of the mangrove forests growing in the lagoon's flood plain died. Presently, efforts are being made to reestablish the original hydrological system. Reforestation of the bare areas is planned with the three dominating mangrove species Avicennia germinans, Laguncularia racemosa and Rhizophora mangle. The objective of the project presented here is to identify the regeneration patterns in the study area. Experiments under controlled conditions and measurements at bare and forested sites carried out from 1994 to 1996 showed that regeneration is possible. However, as the bare areas are large and presently very few or no propagules arrive naturally, regeneration will be slow. Therefore, reforestation is recommended to accelerate the process. In the forests, the seedling growth is mainly controlled by changes in salinity and the mortality by seasonal flooding, while in the bare areas, regeneration is aggravated by extremely high salinities, high soil temperatures and dessication of the top soil layers. The establishment of the small A. germinans and L. racemosa propagules is especially difficult, because they cannot establish themselves in flooded soils and in direct sunlight they dry out rapidly. The seedlings of both species are also very sensitive to changes in water level, wind, waves, temperatures exceeding 45 °C and dry soils. In A. germinans, phytophagous insects affect the chances for survival also. Therefore, mortality in both species is extremely high. R. mangle is much more resistant to most detrimental factors observed with the exception of high salinities. However, there is one favourable factor at the open sites. When sufficient water is present and salinities as well as temperatures are low enough, the high light availability increases growth rates and survival.
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  • 56
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 398-399 (1999), S. 361-373 
    ISSN: 1573-5117
    Schlagwort(e): production ; mathematical model ; Ecklonia cava ; light ; temperature ; photosynthesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The dependence of photosynthesis on light and temperature is modelled through analysis of transition probabilities of photosystems. In the model, two transition probabilities are functions of light, and one transition probability is a function of temperature. The estimated light-saturated photosynthesis of Ecklonia cava blades at 20 °C was 0.037 mg C cm−2 h−1. The value of the activation energy, the standard enthalpy and the standard entropy were estimated to be 56.5 kJ mol−1, 204 kJ mol−1 and 678 J mol−1 K−1, respectively. A production model (an integral photosynthesis model) for an E. cava stand was developed using the photosynthesis model. Production calculated by the model agreed well with observed data during the growing period of an E. cava stand at a field observation site on the west side of Miura Peninsula, Japan. Results of the analysis of the effects of irradiance and temperature on the production of the E. cava community by the model are: 1. Production decreased with irradiance decrease. The estimated compensation irradiance was 26.5 μmol photons m−2 s−1 when the biomass was 3 kg wet mass m−2 (blade:stipe ratio = 2 kg m−2:1 kg m−2) and the temperature was 20 °C. 2. The optimum temperature decreased when irradiance decreased and when biomass increased. The highest estimated value for the optimum temperature was 24.0 °C. The estimated optimum temperature was 18.2 °C when the biomass was 12 kg wet mass m−2 and the photon irradiance was 200 μmol photons m−2 s−1. 3. The amount of biomass that resulted in the maximum production was influenced by irradiance and temperature. At 400 μmol photons m−2 s−1 and 20 °C, the estimated value of the biomass (blade:stipe = 2:1) giving the maximum pr oduction was about 5.3 kg wet mass m−2. However, at 100 μmol photons m−2 s−1 and 24 °C, the estimated value was about 3.0 kg wet mass m−2. The estimated values of the maximum production under the two conditions were 1.05 and 0.30 g C m−2 h−1, respectively.
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  • 57
    Digitale Medien
    Digitale Medien
    Springer
    Environmental biology of fishes 54 (1999), S. 219-227 
    ISSN: 1573-5133
    Schlagwort(e): temperature ; energy partitioning ; nitrogen balance ; salmonid ; fish
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The feed intake, growth, oxygen consumption and ammonia excretion of juvenile Arctic charr were measured over period of four weeks at different temperatures which were either constant (11.0, 14.4, 17.7 °C) or fluctuated daily (14.3 ± 1 °C). Maximum feed intake was estimated to occur at 14.3 °C, while oxygen consumption and nitrogen excretion were highest at the highest temperature, and growth rate was estimated to be highest at 13.9 °C. Feed conversion efficiency was estimated to be highest at 13.2 °C, where over 62.7% of ingested energy was allocated to growth. Metabolic rate accounted for 16–30% of ingested energy and nitrogen excretion was under 3% of ingested energy. The nitrogen budget was under similar thermal influences to the energy budget. Thermal fluctuation increased metabolic rate, but not feed intake, leading to a reduction in feed conversion efficiency under fluctuating temperature conditions.
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  • 58
    ISSN: 1573-5133
    Schlagwort(e): ecophenotypism ; branchial sieve ; geographic variation ; fish ; meristics ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A marked salinity-related decrease in gillraker number in sea bass samples during growth was documented. All specimens share the same genetic stock and rearing conditions were constant during early ontogeny. Variation in gillraker number could be related to the ecophenotypism of this character but selection can not be excluded. Results obtained from reared specimens were compared with those reported in the literature and with data collected from wild stocks. Attention is focused on the pitfalls that the use of this character may have on the taxonomy of fish species.
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  • 59
    Digitale Medien
    Digitale Medien
    Springer
    Biogeochemistry 44 (1999), S. 205-220 
    ISSN: 1573-515X
    Schlagwort(e): grassland ; ground water level ; methane ; peat ; temperature ; wetland
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Geologie und Paläontologie
    Notizen: Abstract The area of wet grasslands on peat soil in the Netherlands is slowly increasing at the expense of drained, agriculturally used grasslands. This study aimed (i) to assess the contribution of wet grasslands on peat soil to methane (CH4) emissions, and (ii) to explain differences among sites and between years in order to improve our understanding of controlling factors. For these purposes, a field study was conducted in the period 1994–1996 in the nature preserve “Nieuwkoopse Plassen”, which is a former peat mining and agricultural area. Net CH4 emissions were measured weekly to monthly with vented closed flux chambers at three representative sites, and at ditches near these sites. Three-years average of CH4 emissions was 7.9 g CH4 m- 2 yr-1 for Drie Berken Zudde, 13.3 for Koole, and 20.4 for Brampjesgat. Ditches near the sites emitted 4.2–22.5 g CH4 m-2 yr-1. The time-course of CH4 emissions for all experimental sites and years was fit with a multiple linear regression model with ground water level and soil temperature as independent variables. Lowering or raising the ground water level by 5 cm could decrease or increase CH4 emissions by 30–50%. Therefore, ground water level management of these grasslands should be done with care.
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  • 60
    ISSN: 1573-5168
    Schlagwort(e): temperature ; intestine ; nerve stimulation ; serotonin ; substance P ; acetylcholine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The contractility of intestinal smooth muscle of Atlantic salmon (Salmo salar) acclimatized to temperatures of 7 and 14 °C was compared over a prolonged period of time (9 months) in freshwater. Initial studies were carried out on intestine isolated from Atlantic salmon to estimate optimal conditions for contractility. Subsequent studies were carried out with the neurotransmitter/agonist 5-HT and TS, which activates neuronal elements in the intestine, in a Krebs-Henseleit solution containing HEPES buffer maintained at pH 7.85 and at the temperature of the experimental group (i.e., 7 or 14 °C). There was a significant interaction with time and temperature for the maximal response of 5-HT (p=0.005), effective concentration producing 50% of the maximal response (EC50) to 5-HT (p=0.026) and maximal response to TS (p=0.002), demonstrating that gastrointestinal contractility of Atlantic salmon is altered by both time (month) and temperature. No significant changes were found with the effective frequency producing 50% of the maximal response (EF50) to TS. The potency (EC50 of 5-HT) increase between 7 and 14 °C was statistically significant (p=0.026) but the small differences found with potency were most likely not physiologically significant. A time shift was recognized in the maximal responses to 5-HT, by applying a time variable to equations for the curves of the responses. This demonstrated that the curves are similar for both temperatures but alterations in the time of the maximal response changes was different. Thus, there is a delay in the time (month) changes of gastrointestinal contractility related to acclimation temperature and would be an area for future study.
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  • 61
    ISSN: 1573-5168
    Schlagwort(e): phospholipids ; plasma membranes ; fatty acids ; molecular species ; temperature ; membrane fluidity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The fatty acid content, fatty acid molecular species composition, and fluidity of phospholipid vesicles and plasma membranes of livers of fish feeding on phytoplankton (silver carp, Hypophthalmichtys molitrix), zooplankton, (big head carp, Hypophtalmitrix nobilis), higher plants, (grass carp, Ctenopharyngodon idella), and omnivorous fish, (common carp, Cyprinus carpio), adapted to reduced temperatures, was determined. Levels of long chain polyunsaturated fatty acids (PUFAs) were highest in silver and big head carp and lowest in common carp. Differences in long chain PUFAs were poorly reflected in fluidity, determined either by fluorescence anizotropy of 1,6-diphenyl 1,3,5-hexatriene or rotational correlation time of 16-doxyl- stearic acid, of phospholipid vesicles. Phospholipid vesicles of C. caripo and C. idella proved to be slightly more rigid than of H. molitrix and H. nobilis below ca. 15 °C. These differences were not seen with isolated plasma membranes assessed with 1,6-diphenyl 1,3,5-hexatriene. Using electron spin resonance spectroscopy plasma membranes from H. molitrix proved to be more fluid than those from C. carpio below ca. 15 °C. Phosphatidylethanolamines were abundant in 1-monounsaturated, 2-polyunsaturated (18:1/22:6, 18:1/20:4) species with H. molitrix and H. nobilis more rich in these species than C. carpio and C. idella. It is suggested that differences in fluidities of phospholipid vesicles below 15 °C is due to differences in levels of the above molecular species. In native membranes these differences may be masked by proteins and other membrane components. It is also suggested that it is not the fatty acid composition of the ingested food but the specific response of the fish to temperature that is the most important factor controlling the physicochemical properties of membranes during thermal adaptation.
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  • 62
    ISSN: 1439-0361
    Schlagwort(e): Geographic variation ; taxonomy ; Rufous-tailed Hummingbird ; Amazilia tzacatl brehmi ; subspec. nov. ; Trochilidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Von der in Mittelamerika und in NW-Südamerika weitverbreiteten Braunschwanzamazilie (Amazilia tzacatl) wurden mehrere Unterarten beschrieben, von denen in der neueren Literatur drei anerkannt wurden:A. t. tzacatl (De la Llave, 1832) mit einem Vorkommen von NO-Mexiko bis W-Venezuela einschließlich N-Kolumbiens;A. t. jucunda (Heine, 1863) von W-Kolumbien bis SW-Ecuador; undA. t. handleyi (Wetmore, 1963) als Endemit der Panamá vorgelagerten Isla Escudo de Veraguas (Karibik). Letzteres Taxon wird von einigen Autoren als Allospezies angesehen, hier aber lediglich als Unterart bewertet, da offenbar nur morphometrische Unterschiede zu den übrigen Taxa bestehen. Die Ergebnisse der vorliegenden biogeographisch-taxonomischen Analyse belegen, daß die geographische Variation der Art im südlichen Verbreitungsgebiet größer ist als bislang angenommen wurde. Aufgrund signifikanter Unterschiede in den Gefiedermaßen erhält die kolumbianischvenezuelanische Population ihren früheren, eigenständigen taxonomischen Rang (A. t. fuscicaudata Fraser, 1840) zurück. Ein neues Taxon,Amazilia tzacatl brehmi subsp. nov., wird von Nariño, Südwestkolumbien, beschrieben. Diese Unterart tritt offenbar allopatrisch zuA. t. jucunda auf und unterscheidet sich morphometrisch deutlich von konspezifischen Nachbarpopulationen.
    Notizen: Summary The Rufous-tailed Hummingbird (Amazilia tzacatl De la Llave, 1832), a widespread inhabitant of Central America and NW South America, currently comprises two subspecies (A. t. tzacatl andA. t. jucunda). Another taxon of the species complex isA. t. handleyi (Wetmore, 1963), initially described as an allospecies but here regarded only as a subspecies ofA. tzacatl. Based on diverging morphological features, the amount of geographical variation ofA. tzacatl in its South American range suggests the distinction of further populations. As a taxonomical consequence, we recognize the validity ofA. t. fuscicaudata (Fraser, 1840), and describe a new subspecies,A. t. brehmi subspec. nov., from Nariño, Colombia.
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  • 63
    Digitale Medien
    Digitale Medien
    Springer
    Aquaculture international 7 (1999), S. 357-360 
    ISSN: 1573-143X
    Schlagwort(e): feed intake ; growth ; silver trevally (Pseudocaranx dentex) ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Materialart: Digitale Medien
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  • 64
    Digitale Medien
    Digitale Medien
    Springer
    World journal of microbiology and biotechnology 15 (1999), S. 335-338 
    ISSN: 1573-0972
    Schlagwort(e): Anaerobic digestion ; biogas ; pathogens ; survival ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract The survival of certain pathogenic bacteria was studied in anaerobic batch digesters at room temperature (18–25 °C) as well as at 35 °C under laboratory conditions. The survival of Escherichia coli and Salmonella typhi at room temperature was upto 20 days whereas at 35 °C it was only upto 10 days. Shigella dysenteriae was found to be the most sensitive organism which could survive upto 10 days at room temperature and upto 5 days at 35 °C. The longest survival was observed in case of Streptococcus faecalis which could survive upto 35 days at room temperature and 15 days at 35 °C. The survival time of Salmonella typhi increased when the solid contents of the digester were elevated from 9% to 15%.
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  • 65
    Digitale Medien
    Digitale Medien
    Springer
    World journal of microbiology and biotechnology 15 (1999), S. 545-552 
    ISSN: 1573-0972
    Schlagwort(e): Fermentation ; polyene antifungal antibiotic ; Streptomyces ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract A Streptomyces strain UK10 was isolated from Ukrainian soil and identified by taxonomical studies as Streptomyces arenae var ukrainiana. HA-2-91 was isolated from the biomass of S. arenae var ukrainiana and is supposedly a polyene macrolide antibiotic belonging to the tetraene group. HA-2-91 showed promising antifungal activity (in vitro) against yeasts and filamentous fungi, including plant pathogens and dermatophytes and was found to be less toxic in mice than nystatin and rimocidin.
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  • 66
    ISSN: 1573-0867
    Schlagwort(e): ammonium chloride ; ammonium sulphate ; nest placement ; nitrification ; temperature ; urea
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Nitrification occurring in an alkaline sandy loam soil fertilized with urea, ammonium sulphate (AS) and ammonium chloride (AC) was studied in the laboratory at 20°C and 40°C for 30 days. Nitrogen fertilizers were applied as nest of sizes 0.2, 0.5, 1.0 and 2.0 g. Unfertilized control and soil mixed with 50 mg N kg-1 were also included as treatments. Nitrification in all the fertilizer treatments decreased markedly with increasing nest size. At 20°C, differences among the three N sources were not significant at 5 days after incubation but marked differences appeared thereafter. All the N was nitrified by 30 days in case of fertilizers mixed into the soil. In nest placement, nitrification ranged from 30.1 to 75.5%, 28.3 to 74.6% and 35.3 to 88.7% for urea, AC and AS, respectively. When equal amounts of fertilizers were placed in a nest, nitrification occurred at a slower rate with urea than with AC and AS. Rates of nitrification were significantly higher at 40°C than at 20°C. At 20 days, nitrification from different nest sizes ranged from 8.4 to 64.9% and from 24.9 to 87.0% at 20°C and 40°C, respectively. The difference in nitrification at two temperatures were more pronounced at higher nest sizes than at smaller nest sizes. While nitrification with the three N sources decreased linearly with increase in N concentration (nest size) in soil at 40°C, it showed a quadratic relationship at 20°C. At equal N concentration, the highest rate of nitrification occurred with urea and the lowest with AC. At the same rate of applied N (50–2000 mg kg-1), AC and AS increased electrical conductivity of soil by 1.3–9 times that of urea. Apparent mineral N recovery of applied N decreased with the increase in nest size.
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  • 67
    Digitale Medien
    Digitale Medien
    Springer
    Mycopathologia 146 (1999), S. 33-41 
    ISSN: 1573-0832
    Schlagwort(e): entomopathogenic hyphomycete ; vector control ; Chagas disease ; Beauveria bassiana ; Rhodnius prolixus ; humidity ; temperature ; incubation time ; mortality
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The impact of relative humidity (RH) on the infective potential of the isolate Bb INRA 297 of Beauveriabassiana (Bals.) Vuillemin (Deuteromycotina: Hyphomycetes) against first in star nymphs of Rhodnius prolixus Stål. (Hemiptera: Reduviidae) was determined. Fungus-treated insects were exposed to RHs ranged from 75 to 100% at 25 °C. Results clearly showed a threshold of humidity at ca. 96% for high and rapid mortality. After initial exposure to increasing periods of 97% (4, 8, 16, 24, 36 and 48 h) and subsequent transfer to constant lower RHs (43, 53,75 and 86%) at a constant 25 °C, an incubation of at least 48 h at 97% RH was necessary to kill all insects. On changing RHs of 97/75% and different regimes of temperature (15/28 °C,20/25 °C, 25/28 °C,and 25/35 °C), at least 72 h of initial exposure at 97% RH for the 15/28 °C regime, 48 h for the 20°/25°C and25/28 °C regimes and 36 h for25/35 °C were needed to kill all insects over a 6-day incubation time. Delayed exposure to favorable moisture condition (97% RH), significantly affected infection for up to a 3-day delay within the various temperature-humidity regimes tested.
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  • 68
    Digitale Medien
    Digitale Medien
    Springer
    Space science reviews 87 (1999), S. 345-348 
    ISSN: 1572-9672
    Schlagwort(e): coronal hole ; quiet Sun ; density ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Spectra from the Coronal Diagnostic Spectrometer on board SOHO are used to compare density and temperature in coronal hole and quiet Sun regions.
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  • 69
    Digitale Medien
    Digitale Medien
    Springer
    International journal of thermophysics 20 (1999), S. 1257-1266 
    ISSN: 1572-9567
    Schlagwort(e): critical point ; exploding wire technique ; high-pressure cell ; numerical modeling ; specific heat ; tantalum ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract A foil confined in a sapphire cell is heated by an electrical current pulse at rates from 1010 to 1011 K·s−1. Temporal evolutions of the temperature and pressure distributions in the foil is investigated by means of numerical modeling. It is demonstrated that such a technique allows reaching temperatures far above 10,000 K and pressures up to 50 kbar and provides a uniform temperature and pressure in the foil. The technique has been applied for investigation of liquid tantalum. Experimental results on temperature measurement are discussed. Data on specific heat of liquid tantalum at temperatures up to 11,000 K are reported.
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  • 70
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 403 (1999), S. 13-26 
    ISSN: 1573-5117
    Schlagwort(e): Cobitidae ; Cobitis ; taxonomy ; new subgenus ; Turkey
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In the rivers and lakes of Turkey, ten species of loaches of the genus Cobitis occur, viz. C. fahireae, C. varderensis, C. splendens, C. kellei, C. puncticulata, C. strumicae, C. levantina, C. turcica, C. simplicispina and C. bilseli. Cobitis bilseli is separated into a new subgenus, Beyshehiria.
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  • 71
    ISSN: 1573-5117
    Schlagwort(e): Macrothrix laticornis-complex ; morphology ; taxonomy ; distribution ; males
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Macrothix laticornis is redescribed and compared with populations from central North America (Mexico), and from south-east Asia (Vietnam). All three are closely related, but with sufficient morphological differences to establish a laticornis species-group. Two species new for science are described, viz. M. sierrafriatensis (Mexico) and M. vietnamensis (Vietnam).
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  • 72
    ISSN: 1573-5117
    Schlagwort(e): Branchiopoda ; ‘Cladocera’ ; Anomopoda ; Macrothrix tripectinata ; morphology ; redescription ; taxonomy ; key ; Eurasia ; distribution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The rare Macrothrix tripectinata Weisig, 1934 is redescribed on material from the East Pamirs (Tajikistan) and Tuva (Russia). Adult and juvenile parthenogenetic females and adult males were studied using optical microscopy and SEM. The thoracic appendages and the molar surface of mandibles were investigated in detail. Selected ‘conventional’ diagnostic features are critically reviewed. The importance of characters, rarely used in the systematics of Macrothrix, such as: type of valve reticulation, similarity or dissimilarity in size of the terminal esthetascs of the antennules of females and males, presence of an abdominal projection and reticulation on the postabdomen, presence, length and armature of a male seta on the antennule, are discussed. A key for the Eurasian species of Macrothrix is proposed.
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  • 73
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 403 (1999), S. 87-95 
    ISSN: 1573-5117
    Schlagwort(e): Thermocyclops ; China ; taxonomy ; distribution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Based on the result of investigations and former records, there are five freshwater species of the genus Thermocyclops in China, namely T. taihokuensis Harada, 1931, T. crassus (Fischer, 1853), T. vermifer Lindberg, 1935, T. dybowskii (Lande, 1890), and T. kawamurai Kikuchi, 1940. Two previously recorded species, T. brevifurcatus Harada, 1931 and T. hyalinus (Rehberg, 1880) are recognized as synonyms of Thermocyclops crassus. Another species, Thermocyclops mongolicus Kiefer, 1937, described from China by Tai & Chen, is a synonym of T. taihokuensis based on this study. Thermocyclops orientalis Dussart & Fernando, 1985 was compared with Thermocyclops kawamurai Kikuchi, 1940. It shows conspicuous differences and it seems unlikely that it is a synonym of T. kawamurai. The paper presents diagnostic characteristics of each species and a key to five Chinese species of Thermocyclops.
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  • 74
    ISSN: 1573-5117
    Schlagwort(e): aquatic Oligochaeta ; Lake Biwa ; Japan ; taxonomy ; zoogeography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract At least 41 taxa of aquatic oligochaetes including five new records have been recorded from the ancient Lake Biwa in Japan. The lake is characterized by eurybathyal occurrence of Branchiura sowerbyi. The posterior gill filaments of B. sowerbyi develop normally in lagoons adjacent to the lake, while in the lake they weakly develop or often disappear at littoral and sublittoral depths shallower than 30 m, and they almost completely disappear in the profundal zone. The profundal population of B. sowerbyi also differs from other populations in eastern Asia in having fewer and shorter hairs, and simple-pointed crotchets, or bifid crotchets with parallel teeth, in dorsal bundles of chaetae. This suggests that an intralacustrine speciation is progressing in the profundal population. An aberrant modification is found in the pectination of dorsal crotchets in Tubifex tubifex occurring at deep profundal depths of the lake. The ventral chaetae in segment II of Teneridrilus mastix are rarely modified in Lake Biwa. This requires cancellation of the modification of chaetae in II as a diagnostic characteristic of the genus Teneridrilus. Limnodrilus amblysetus, previously known only from China, is recorded from Lake Biwa. Descriptions and taxonomic remarks are provided for Haemonais waldvogeli (new to Japan), Pristina longiseta, Stephensoniana trivandrana and Ripistes parasita (new to Lake Biwa), and Ophidonais serpentina, based on Lake Biwa material.
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  • 75
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 400 (1999), S. 129-140 
    ISSN: 1573-5117
    Schlagwort(e): fish ; energetics ; temperature ; feeding ; prey abundance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract I examined food consumption and growth of walleye larvae in extensive culture ponds using direct methods and a bioenergetics model, and compared my results with laboratory feeding and growth studies. Walleye showed a diel pattern of increasing gut fullness during daylight hours. Larvae exhibited lower maximum food consumption rates in the ponds than predicted from previous short-term laboratory feeding studies. Direct estimates and bioenergetics model estimates of daily food consumption in the culture ponds were in poor agreement and the discrepancy varied with respect to walleye size. Food consumption rates in the ponds were related to walleye size (direct estimates) or water temperature (bioenergetics model estimates) but not zooplankton abundance. Growth exceeded 0.10 g g−1 d−1 for all but one sampling interval and the maximum growth rate in the culture pond fish was double the maximum growth rate determined in the laboratory. Growth was positively related to pond temperature and negatively related to walleye mass, but was not significantly related to zooplankton abundance. Gross conversion efficiency was negatively related to walleye mass, positively related to zooplankton abundance and not related to temperature. Food consumption and growth of walleye larvae in the field may be food-limited at much lower prey abundances than previous laboratory research has suggested.
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  • 76
    ISSN: 1573-5117
    Schlagwort(e): Gracilaria ; growth ; irradiance ; plant growth regulators ; salinity ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Growth and tolerance of Gracilaria vermiculophylla (Ohmi) Papenfuss from Shikoku Island were investigated under a variation of temperature (5–30 °C), salinity (5–60‰), and photon irradiance (20–100 μmol photons m−2 s−1) in unialgal culture. G. vermiculophylla showed wide tolerances for all factors tested, characterizing a euryhaline and eurythermal species. Two clones, one of a tetrasporophyte and the other of a female gametophyte, showed different growth rates, attributable to the difference either in phase or in genotype. The optimum temperature for the growth of the tetrasporophyte clone was 15–25 °C while that of the gametophyte clone was 20–30 °C. Maximum growth of both phases was observed at 80–100 μmol m−2 s−1. G. vermiculophylla presented higher growth rates in low salinities (15–30‰). Tissue cultures were established in solid ASP 12-NTA medi um supplemented with plant growth regulators (PGR), 0.5% agar, 1.0% sucrose and 0.5% inositol. Effects of two auxins (indole-3-acetic acid (IAA), and 2,4-dichlorophenoxyacetic acid (2,4-D)), and one cytokinin (6-benzylaminopurine (BA)) were tested in concentrations ranging from 0.1 to 10.0 mg l−1. Growth of apical segments was significantly stimulated by the majority of treatments supplemented with PGR, while maximum growth of calluses was observed in treatments with low concentration of auxins or BA (1.0 mg l−1). All treatments supplemented with PGR significantly promoted the growth of intercalary segments, except for IAA (1.0 mg l−1) in combination with BA (1.0 mg l−1). Growth of calluses originating from intercalary segments was observed in treatments with IAA (0.1 mg l−1), 2,4-D (10.0 mg l−1) or IAA (1.0 mg l−1) in combination with BA (0.1 mg l−1). Tr eatments with high concentration of IAA and BA (10.0 mg l−1) were lethal for apical and intercalary segments. These results show that auxin and cytokinin play a regulatory role on the growth of G. vermiculophylla in tissue culture. Furthermore, results on the effects of temperature, salinity and irradiance indicate that G. vermiculophylla could be cultivated in brackish temperate environments with potential for economic purposes and for pollution management.
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  • 77
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 398-399 (1999), S. 65-74 
    ISSN: 1573-5117
    Schlagwort(e): Australia ; Coral Sea ; marine algae ; taxonomy ; biogeography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The marine benthic algae from North East Herald Cay, Coral Sea, South Pacific, are listed with taxonomic, bibliographic and biogeographic details. The checklist includes 66 species of which 23 are green, 2 are brown, and 41 are red algal species. The almost complete absence of brown algae from what is seemingly a typical tropical reef environment on which a true coral cay has developed is noteworthy. All samples were from the lagoon, which forms the concave side of a crescent-shaped reef and which ranges in depth from 0–30 m. The endemic Caribbean green alga Chamaedoris peniculum is recorded for the Pacific for the first time, and a possibly undescribed species of the genus Rhipiliopsis was also discovered. Although only preliminary, the survey shows that the marine flora is seemingly typical of coral cays for the general region of the Great Barrier Reef.
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  • 78
    ISSN: 1573-5117
    Schlagwort(e): photosynthesis ; respiration ; Gelidiella acerosa ; culture ; tidal habitat ; salinity ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Several samples of the red seaweed, Gelidiella acerosa (Forssk.) Feldmann & Hamel occurring in tidepools, high intertidal rocks, and shallow subtidal areas on a reef flat in Ilocos Norte, northern Philippines were studied in terms of their photosynthetic and respiratory responses (μl O2 gDW−1 h−1) to four salinity (22, 28, 34, 40‰) and three temperature (22, 28, 34 °C) combinations. The upper intertidal plants tolerated low salinities (22–28‰) better than high salinities (34–40‰), while tidepool and subtidal plants were not affected. Temperatures of 22 through 34 °C resulted in a one-fold increase in their photosynthetic rates and insignificant differences in their respiratory rates while tidepool and subtidal plants almost doubled their photosynthetic rates and their respiration rates increased by about 5–50 times. There were no interaction effects. Therefore, intertidal plants appe ared to be more tolerant to wide temperature fluctuations and low salinity levels; while tidepool and subtidal plants were least affected by salinity variations but were quite sensitive to temperature fluctuations. Vegetative and tetrasporic plants had similar photosynthetic and respiratory responses to salinity and temperature variations, although vegetative plants had significantly higher net photosynthesis under the minimum and maximum temperatures tested (22 and 34 °C). Reproductive G. acerosa showed greater tolerance to temperature fluctuations. These responses indicated that physiological changes may have occurred when the species became reproductive. Tolerance of G. acerosa to low salinities suggests that lowering the salinities in culture tanks could be used to eradicate contaminants, i.e., dinoflagellates and filamentous green algae. Temperature of 28 °C appeared to be optimum for all plant types as reflected by their high photosynthetic and low respiratory rates .
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  • 79
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 406 (1999), S. 9-19 
    ISSN: 1573-5117
    Schlagwort(e): Annelida ; Clitellata ; history ; taxonomy ; ecology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Fourteen aquatic oligochaetes were described between 1773 and 1828. Dramatic increases in descriptions occurred in the decades beginning 1900, 1930 and 1960. These can be associated with specific authors, such as W. Michaelsen and S. Hrabě. In the period 1970–1990, some 250 marine species (excluding Enchytraeidae) were described, largely by C. Erséus. Some of the major scholars, such as W. Michaelsen and F. Vejdovský, I. I. Malevič and P. G. Svetlov, founded centers of oligochaete study that survive in Europe today. Others, such as those in the English speaking world, have had to develop in isolation. While numerical and phenetic methods had little influence on microdrile systematics, phylogenetic (parsimony) methods have, since the first publication by B. G. M. Jamieson. Most literature prior to 1970 was taxonomic. Other earlier work documented community structure in relation to pollution. The study of Rybinsk Reservoir (Russia) stimulated a large body of ecological and biological work by T. L. Poddubnaya. The St. Lawrence Great Lakes was also a focus for worm studies until recently. Early physiological work focused on respiration, with studies dating from the 1920s. This has been continued in relation to pollution ecology and energy flow. Physiological work was notably absent from our first proceedings volume and only poorly represented since then. Future prospects are difficult to identify. Developments in ultrastructure (including sperm and muscle cells), molecular biology and parsimony or cladistic phylogenetic methods will move from rather simple initial work that shows the possibilities, to a revisionary phase where the complexities begin to be revealed before it is possible to assess their value. This author has too superficial a level of understanding to predict the outcome, but suspects that agreement among the results of several methods is needed for them to be persuasive. I would hope that multivariate methods of data analysis in pollution studies would prove superior to the development of indices and over-reliance on toxicology. Toxicity studies are of use in comparing risks among products but not in predicting field effects. Benthic biology needs a method for identifying factors that are directly related to worm biology, such as food, rather than physical and chemical factors related to the water column. Surveys, relating communities to chemical and physiographic factors will remain unpredictive. It is easier to forsee some changes in taxonomy that are almost overdue. The haplotaxids should be broken up into several small families, Haplotaxis s.s. will be one of them, with a number of highly adapted and very similar species, many currently regarded as synonymous, redefined by careful anatomical study. The lumbriculids and branchiobdellidans may well be combined into a single taxon defined by their unique semi-prosopore male ducts, with lumbriculids defined by their unique muscle structure and the branchiobdellids by many apomorphic characters related to ectocommensal life. The position of Hirudinea remains unresolved, but relationship to this taxon is not excluded. Detailed study of penes in lumbriculids is required. The naidids and tubificids seem to be a monophyly. Existing genera may be hard to analyze phylogenetically because definitions are based on atrial form, which is hard to express as characters. Chaetotaxy in Naididae will prove insufficient and many synonyms will be declared. Capilloventridae and Randiellidae require description of male ducts and gonads. They may provide evidence counter to the octogonadal theory of oligochaete descent, or of polyphyly in the group. Knowledge of phreodrilid diversity will increase. Work will increase in Asia and South America, but sub-Saharan Africa remains under explored. Fish diseases will create more interest in North American worms. New methods, including molecular studies, and renewed interest in ontogeny and detailed anatomical studies, may improve our ability to resolve clusters of taxa with few, if any, apomorphic character states that remain at the base of cladograms. An ability to include sound evidence from vestigial organs and logical arguments on a 'weight of evidence' basis is needed as an adjunct. While molecular studies seem to hold much promise, early studies can prove over simplistic and can provide conflicting hypotheses. We need to complete the review of taxonomy according to parsimony before major terminology changes, such as abandonment of the term Oligochaeta, can gain acceptance.
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  • 80
    ISSN: 1573-5117
    Schlagwort(e): mitochondrial DNA ; cytochrome oxidase I ; competitive PCR ; copepoda ; taxonomy ; marine zooplankton
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Accurate taxonomic identification of species at all life stages is critical to understand and predict the processes that together determine marine community dynamics. However, zooplankton assemblages may include numerous sibling and congeneric species distinguished by subtle morphological characteristics. Molecular systematic databases, including DNA sequences of homologous gene regions for selected taxonomic groups, allow the design of rapid protocols to determine species' diversity and identify individuals. In this study, the DNA sequence of a 300 base-pair region of the mitochondrial cytochrome oxidase I (COI) gene was determined for eight species of three genera of calanoid copepods: Calanus finmarchicus, C. glacialis and C. helgolandicus; Neocalanus cristatus, N. flemingeri and N. plumchrus; and Pseudocalanus moultoni and P. newmani. The DNA sequences differed between congeneric species by 13 – 22% of the nucleotides; the protein sequences differed by zero to five amino acid substitutions. Both the DNA and amino acid sequences resolved the evolutionary relationships among congeneric species; relationships among the genera were not well-resolved by this region of mtCOI. Using the same conserved primers, the only amplification product for C. finmarchicus was an aberrant sequence (and putative pseudogene) which differed from the C. finmarchicus COI sequence by 36% of the nucleotides and 32 amino acid substitutions. Species-specific oligonucleotide primers were designed for Calanus spp. (which cannot be distinguished at larval stages) and Pseudocalanus spp. (which are difficult to distinguish even as adults). Individual copepods were identified using competitive, multiplexed species-specific polymerase chain reactions (PCR) in two studies of co-occurring sibling species. The first study confirmed the presence of three Calanus spp. in Oslofjord, Norway and found a predominance of C. helgolandicus. The second study determined patterns of distribution and abundance of Pseudocalanus spp. on Georges Bank in the NW Atlantic and showed that P. moultoni predominated in shallow and coastal waters, while P. newmani was more abundant in offshore regions flanking the Bank. Competitive, species-specific PCR is a useful tool for biological oceanographers. This simple, rapid, and inexpensive assay may be used to identify morphologically-similar individuals of any size and life stage, and to determine a species' presence or absence in pooled samples.
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  • 81
    Digitale Medien
    Digitale Medien
    Springer
    Biogeochemistry 44 (1999), S. 205-220 
    ISSN: 1573-515X
    Schlagwort(e): grassland ; ground water level ; methane ; peat ; temperature ; wetland
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Geologie und Paläontologie
    Notizen: Abstract The area of wet grasslands on peat soil in the Netherlands is slowly increasing at the expense of drained, agriculturally used grasslands. This study aimed (i) to assess the contribution of wet grasslands on peat soil to methane (CH4) emissions, and (ii) to explain differences among sites and between years in order to improve our understanding of controlling factors. For these purposes, a field study was conducted in the period 1994–1996 in the nature preserve “Nieuwkoopse Plassen”, which is a former peat mining and agricultural area. Net CH4 emissions were measured weekly to monthly with vented closed flux chambers at three representative sites, and at ditches near these sites. Three-years average of CH4 emissions was 7.9 g CH4 m−2 yr−1 for Drie Berken Zudde, 13.3 for Koole, and 20.4 for Brampjesgat. Ditches near the sites emitted 4.2–22.5 g CH4 m−2 yr−1. The time-course of CH4 emissions for all experimental sites and years was fit with a multiple linear regression model with ground water level and soil temperature as independent variables. Lowering or raising the ground water level by 5 cm could decrease or increase CH4 emissions by 30–50%. Therefore, ground water level management of these grasslands should be done with care.
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  • 82
    Digitale Medien
    Digitale Medien
    Springer
    Reviews in fish biology and fisheries 9 (1999), S. 325-352 
    ISSN: 1573-5184
    Schlagwort(e): evolution ; nomenclature ; phylogeny ; species ; systematics ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract It is argued, with selected examples from freshwaterfish systematics, that species should be viewed as anexpression of self-perpetuated clustered variation innature, conforming to the phylogenetic speciesconcept. The importance of species lies in thefunctional and structural significance of theirdiagnostic characters. Species can be nested by theircharacters into a tree diagram (phylogeny) orhierarchical alignment structure (classification) ofcharacter distribution, which may be taken to reflectevolution, the unifying theory of organismaldiversification. The phylogenetic species concept,which emphasizes recognition of a pattern ofvariation, describes better than any other proposedconcept the units called species by systematists.Other concepts are based on processes and normally donot permit recognition of particular taxa. Specieshave unique histories, and speciation may proceed bydifferent mechanisms. Whereas it may be postulatedthat speciation entails an irreversible change in thegenetic structure of taxa, recognized by phenotypicexpression and apparently also maintained to a largeextent by selection for a particular phenotype,species recognition must remain independent ofassumptions about species history and spatialdistribution. Species are monophyletic taxa and thespecies category does not differ significantly inphylogenetic regard from other systematic categories.Species as such are not necessarily evolutionaryunits. It is recommended to apply species names withreference to the diagnostic characters of the speciesand to abandon the type specimen described by theInternational Code of Zoological Nomenclature as anomenclatural reference unit.
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  • 83
    ISSN: 1572-9540
    Schlagwort(e): muon ; fusion ; isotope exchange ; temperature ; target
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract A mathematical model describing the kinetics of establishing equilibrium is developed. Equilibrium concentrations of isotopic molecules for gas mixtures used in muon catalyzed fusion research are calculated.
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  • 84
    Digitale Medien
    Digitale Medien
    Springer
    Photosynthetica 37 (1999), S. 339-363 
    ISSN: 1573-9058
    Schlagwort(e): chemicals ; circadien cycle ; dark-adapted state ; fast kinetics ; fluoranthene ; light-adapted state ; photosystem 2 ; slow kinetics ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The review summarizes basic information about slow and fast chlorophyll (Chl) a fluorescence induction kinetics (FIK) recorded using fluorimeters working on a principle of the pulse amplitude modulation (PAM) of a Chl fluorescence signal. It explains fundamental principles of the measuring technique, evaluates the terminology, symbols, and parameters used. Analysis of Chl FIK resulting in a set of Chl fluorescence parameters (FPs) provides qualitative and quantitative information about photosynthetic processes in chloroplasts. Using FPs, one can describe the functioning of the photosynthetic apparatus under different internal and external conditions. Brief comments on proper application of the fluorimetric method in photosynthesis research and some actual examples are also given.
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  • 85
    Digitale Medien
    Digitale Medien
    Springer
    Netherlands journal of geosciences 78 (1999), S. 179-189 
    ISSN: 1573-9708
    Schlagwort(e): biostratigraphy ; Fiji ; Gastropoda Indonesia ; Miocene ; Mollusca ; Pteropoda ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie
    Notizen: Abstract Pteropoda (Mollusca, Gastropoda, Euthecosomata) described by Beets (1943, 1950, 1953) from the alleged Late Miocene/Early Pliocene asphaltic deposits of Buton (SE Sulawesi, Indonesia) are revised. The following species are distinguished: Styliola subula (Quoy & Gaimard, 1827), Cavolinia bituminata (Beets, 1953), Cavolinia mexicana (Collins, 1934), Cavolinia vendryesiana (Guppy, 1873) and Diacria mbaensis Ladd, 1934. A comparison with the Fiji pteropod associations suggests a Miocene (Tortonian to Messinian) age for the Indonesian faunules. Pteropod species described by Ladd (1934) from Viti Levu (Fiji Islands), are revised in an appendix. Five species are distinguished, viz. Creseis acicula (Rang, 1828) (?), Cavolinia gypsorum (Bellardi, 1873), C. mexicana, C. rewaensis (Ladd, 1934) and Diacria mbaensis Ladd, 1934. The presence of Cavolina gypsorum dates this association as Miocene (Tortonian–Messinian).
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  • 86
    Digitale Medien
    Digitale Medien
    Springer
    Netherlands journal of geosciences 78 (1999), S. 215-229 
    ISSN: 1573-9708
    Schlagwort(e): Actinopterygii ; Coccolepidae ; Halecomorphi ; Halecostomi ; taxonomy ; Teleostei
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie
    Notizen: Abstract An overview is presented of the actinopterygian fishes from the Late Jurassic (Late Kimmeridgian and Early Tithonian) ‘Plattenkalke’ near Solnhofen (Solnhofen lithographic limestone), Bavaria, Germany. The fish fauna is very diverse, with the palaeonisciform Coccolepis, halecostomes such as Lepidotes, Heterostrophus, three genera of macrosemiids and six genera of pycnodontiforms, halecomorphs including two genera of caturids, two genera of amiids, Ophiopsis, ‘Furo’, Ionoscopus, Brachyichthys, Callopterus, Liodesmus, ?Lophiurus, five genera of pachycormids, three genera of pholidophorids, Pleuropholis, two genera of aspidorhynchids and eleven genera of basal teleosts. Although several groups have been subject of revision, most of the fauna remains poorly known. Study of this rich fauna will provide a lot of information on the phylogeny and interrelationships of halecostome fishes.
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  • 87
    Digitale Medien
    Digitale Medien
    Springer
    Netherlands journal of geosciences 78 (1999), S. 267-280 
    ISSN: 1573-9708
    Schlagwort(e): ‘Agnatha’ ; biostratigraphy ; Gnathostomata ; Ludlovian ; Pridolian ; taxonomy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie
    Notizen: Abstract The fauna from a Late Silurian residue sample from Övedskloster (Skåne) is listed. It comprises scales of ‘Agnatha’ (rare osteostracan scales, and the thelodonts Thelodus parvidens, ‘T. traquairi’, T. sculptilis, T. admirabilis, and ‘Loganellia cuneata’) and of Gnathostomata (the acanthodians Nostolepis striata, Gomphonchus sandelensis, Poracanthodes? lehmani sp. nov., and Poracanthodes cf. punctatus, tesserae of the head and other specialised elements of the squamation; and the osteichthyan Andreolepis hedei). This fauna is considered to be as old as, or slightly younger than that from the complex of sedimentary rocks along the Anglo-Central Urals margin of the Laurussian continent affected by the Ludfordian A. hedei Event. This event marks the transition between the hedei and sculptilis Zones of the Microvertebrate Standard Zonation and can be correlated with the snajdri Conodont Interval Zone. The evidence favours a simultaneous palaeogeographical appearance of the punctatiform and porosiform poracanthodid acanthodians within the Baltica region of Laurussia.
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  • 88
    ISSN: 1573-9058
    Schlagwort(e): chlorophyll ; dry mass ; leaf number and area ; peg ; pod ; saccharides ; stomatal conductance ; temperature ; transpiration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Net photosynthetic rate (PN) was studied in field-grown peanut cv. GG 2 in relation to leaf position, time of day, reproductive-sink, and phenophase. In general, PN remained higher in the upper leaves (first from top to the fourth) than in the lower leaves (fifth to eighth). The mean PN of the leaves situated upper and the leaves lower in the canopy increased from the morning, reached a maximum during noon hours, and decreased thereafter. Between 09:00 to 10:00 h, PN, stomatal conductance (gs), and transpiration rate (E) in the upper leaves were higher than in the lower leaves, but between 12:00 and 13:00 h, these activities increased significantly in the lower leaves. Highest PN was found during pod-development phase. Removal of flowers, and hence of active reproductive-sink, decreased plant height and number of leaves, and initiated accumulation of photosynthates in the leaves. The PN per unit leaf area in plants with reproductive-sink (WRS) was similar to those without reproductive-sink (WORS). However, leaf area of WORS plants decreased significantly, mainly due to the reduction in number of leaves. No feed-back inhibition of PN (per unit leaf area) was found despite accumulation of photosynthates in the leaves as a result of removal of the active reproductive-sink.
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  • 89
    ISSN: 1573-9058
    Schlagwort(e): Amphisorus ; Amphistegina ; chlorophyll fluorescence kinetics ; electron transport ; irradiance ; photosynthesis ; photosystem 2 ; quantum yield ; Sorites ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Coral reef bleaching is a global phenomenon poorly understood today. We investigated during 7 d the photosynthetic behaviour of symbionts of coral reef and temperate foraminifers in hospite, by means of the JIP-test. By this screening test the fast fluorescence rise O-J-I-P, measured by a Plant Efficiency Analyser (PEA) with 10 µs time resolution and 12 bit signal resolution, was analysed. It informs about the structure and function of photosystem 2 being at different physiological states established by adaptation to different irradiance and temperature. The test needs a measuring time in vivo of only 1 to 5 s, and thus many samples can be analysed. The measurements can be done continuously even on a single cell in a test tube or on the reef. The reef foraminifers tested here were Amphistegina and Amphisorus, freshly collected in Mauritius. As a temperate foraminifer, Sorites from the Mediterranean Sea was tested. The cells are very sensitive to slight temperature changes (25 to 32 °C). The comparison showed that the more the foraminifers live in an environment with constant temperature the less they are able to respond to temperature changes and, thus, the less they can adapt. Rising the temperature increases in general the sensitivity to different stress factors, such as high irradiance, pH, CO2, etc. After the test series, the cells recovered fully and were kept in an aquarium for long time observation.
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  • 90
    ISSN: 1573-9058
    Schlagwort(e): QA and QB sites ; temperature ; thermoluminescence ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract F0 fluorescence and thermoluminescence (TL) were recorded simultaneously on various dark-adapted leaf samples. Above 40 °C, a sharp peak of TL coincided with the onset of the heat-induced F0 rise. It results from a back-transfer of an electron from the secondary QB -to the primary acceptor QA of photosystem 2, followed by a luminescence-emitting recombination with Tyr-D1. This demonstrates that the critical temperature at which the F0 starts rising also corresponds to a shift towards the left of the QA↔QB - equilibrium.
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  • 91
    Digitale Medien
    Digitale Medien
    Springer
    Mechanics of time-dependent materials 3 (1999), S. 141-157 
    ISSN: 1573-2738
    Schlagwort(e): CFRP ; fatigue ; frequency ; stress ratio ; temperature ; viscoelasticity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract A prediction method of fatigue strength under an arbitraryfrequency, temperature, and stress ratio is proposed for polymercomposites and its validity is confirmed for the flexural fatiguestrength of satin-woven CFRP laminates. This method is based upon fourhypotheses: (a) same failure process under constant strain-rate (CSR),creep, and fatigue loadings, (b) same time-temperature superpositionprinciple for all failure strengths, (c) linear cumulative damage lawfor nondecreasing stress process, and (d) linear dependence of fatiguestrength upon stress ratio. This method was applied to the flexuralfatigue strength of various unidirectional CFRPs, and the verificationand limitations of this method were discussed.
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  • 92
    Digitale Medien
    Digitale Medien
    Springer
    Interface science 7 (1999), S. 251-271 
    ISSN: 1573-2746
    Schlagwort(e): triple junctions ; taxonomy ; dimensionality ; structure ; energy ; segregation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Abstract We provide an overview of the properties of triple junctions and quadruple points. It is shown that these junctions may exhibit distinct behaviors that imply that they have and thermodynamically distinct properties in the same way that grain boundaries can be considered as thermodynamically distinct phases, separate from the material that they inhabit. It is shown that the treatment of triple junctions as thermodynamically distinct defects is a natural extension of the treatment of grain boundaries, and that it can be further extended to other junctions such as quadruple nodes. Equilibrium dihedral angles under conditions of anisotropic interfacial energy are explored, and it is found that the dihedral angles may be variable under a range of different conditions.
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  • 93
    Digitale Medien
    Digitale Medien
    Springer
    Evolutionary ecology 13 (1999), S. 395-409 
    ISSN: 1573-8477
    Schlagwort(e): body size ; development ; Drosophila melanogaster ; dung flies ; growth ; life history ; resource limitation ; Scathophaga stercoraria ; seasonality ; Sepsis cynipsea ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Growth responses to temperature and resource limitation in three dipteran species with similar life histories were compared. With respect to current life history theory, two points are raised. First, growth rate in real time increased steeply with temperature in all species, following the standard pattern. However, when expressed in physiological time growth rate increased as temperature decreased in the yellow dung fly Scathophaga stercoraria, remained approximately constant in Sepsis cynipsea, and increased in Drosophila melanogaster. These responses can be understood as adaptations to climate and seasonality. It is concluded that some patterns of adaptation may be more easily interpreted if, and some may even go undetected unless, they are analysed in physiological time. Second, a decrease in body size, development rate and growth rate when resources are limited is believed to be nearly universal and generally predicted by life history models. Despite their similar life histories, the three species investigated showed qualitatively different growth responses to larval food shortage. At unlimited resources, yellow dung flies showed the fastest initial larval body mass gain per unit time, while those of S. cynipsea and D. melanogaster were lower and about equal. The period of no body mass gain at the end of larval development was longest in S. stercoraria and shortest in S. cynipsea. When facing resource limitation, S. stercoraria emerged smaller but earlier (thus nearly maintaining their growth rate), S. cynipsea smaller after the same development period, and D. melanogaster smaller and later (showing reduced and much reduced growth, respectively). It is concluded that whether growth really slows when resources are limited depends on the precise ecological circumstances of the species in question. More refined models, particularly those where mortality costs are independent of time, and more experiments are necessary to account for the variation in growth and size and age at maturity present in nature.
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  • 94
    ISSN: 1573-8248
    Schlagwort(e): Macrolophus pygmaeus ; photoperiod ; predation rate ; temperature ; predator
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The effect of temperature and photoperiod on the rate of predation of nymphs and adults of the predator Macrolophus pygmaeus was studied using Myzus persicae prey feeding on egg-plant and pepper plants. The experiments were conducted at three photoperiods (16L:8D, 12L:12D and 8L:16D), three temperatures (20, 25 and 30 °C), and at 65% r.h. The rate of predation increased with temperature. Predation rate was affected by photoperiod on pepper but not on egg-plant. Females and fifth instar nymphs were the most voracious stages followed by third and fourth instar nymphs and males. First and second instar nymphs consumed far fewer aphids. Predation rate was higher on leaves of pepper than egg-plant, especially at 30 °C. Variation in the efficacy of this predator is discussed.
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  • 95
    ISSN: 1573-8248
    Schlagwort(e): biological control ; Botrytis aclada ; Botrytis cinerea ; cyclamen ; ecological adaptation ; hydrangea ; lily ; onion ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Ulocladium atrum and Gliocladium roseum are fungal antagonists capable of suppressing sporulation of Botrytis spp. on dead plant parts. The effect of temperature (3 to 36 °C) on antagonist conidial germination and mycelial growth was assessed on agar. In addition conidial germination of U. atrum was measured on dead lily leaves. The optimum temperature of both antagonists for both conidial germination and mycelial growth was between 27 and 30 °C. U. atrum was less affected by lower temperatures than G. roseum. At optimum temperature, 50% of conidia of U. atrum and G. roseum germinated within 2.6 and 10.0 hrs, respectively. At low sub-optimal temperatures (6 °C), 50% of conidia germinated within 18 and 96 hours, respectively. In bioassays on dead onion leaves, U. atrum suppressed sporulation of B. cinerea and B. aclada at all temperatures tested (6 to 24 °C) by more than 85%. On dead cyclamen leaves, G. roseum was more efficient than U. atrum at 21 and 24 °C but, in contrast to U. atrum, showed no antagonistic activity at temperatures below 21 °C. On dead hydrangea leaves, U. atrum significantly reduced sporulation of B. cinerea at temperatures as low as 3 and 1 °C. Under Dutch growing conditions, the mean air temperature during leaf wetness periods in onion and lily fields was 15 °C with temperatures only occasionally above 20 °C. In greenhouse crops of cyclamen, the mean temperature during high humidity periods was 17 °C. It is therefore concluded that U. atrum is better adapted than G. roseum to temperatures which occur in the field, in greenhouse crops such as cyclamen, or during cold storage of plant stocks.
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  • 96
    Digitale Medien
    Digitale Medien
    Springer
    Experimental mechanics 39 (1999), S. 86-91 
    ISSN: 1741-2765
    Schlagwort(e): Acousto-ultrasonic ; damage monitoring ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract The acousto-ultrasonic (AU) technique can be a useful methodology for monitoring structures or mechanical components during endurance tests, fatigue tests or, in general, during the life of the components. To obtain reliable information about the failure and fatigue cracks at their earliest initiation stages and to follow their evolution regardless of any disturbance effects, refined experimental procedures and signal processing are needed. In particular, the effects of temperature variation cannot be entirely suppressed and are difficult to evaluate. This means that the results of the AU technique are not immediately interpretable and usable for monitoring structures. This paper describes some procedures aimed at minimizing the effects of disturbance on AU signals caused by temperature variation, allowing use of AU for monitoring over extensive periods of time or when the component is subjected to heating.
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  • 97
    ISSN: 1439-0361
    Schlagwort(e): mate choice ; taxonomy ; phenotypic hybrids ; fitness ; decision rule
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die als Unterarten klassifizierten europäischen Formen der Aaskrähe, Rabenkrähe und Nebelkrähe, besiedeln verschiedene, aneinandergrenzende Verbreitungsgebiete und hybridisieren in der Kontaktzone. Die Nachkommen von Mischpaaren sind fruchtbar und können sowohl mit anderen Hybriden als auch mit Raben- und Nebelkrähen erfolgreich brüten. Trotzdem kommt es zu keiner völligen Vermischung der Formen und/oder Verlagerung der Verbreitungsgebiete. Vor diesem Hintergrund untersuchten wir die Partnerwahl von Aaskrähen in der Hybridisierungszone auf der nordfriesischen Insel Amrum und stellten fest, daß Partner gleichen Phänotyps häufiger miteinander verpaart waren, als stochastisch zu erwarten gewesen wäre. Unsere Daten bestätigen vergleichbare Studien aus Hybridisierungszonen in Italien und Sibirien. Wir schließen daraus, daß phänotypisch selektive Partnerwahl bei der Aaskrähe ein allgemeines Phänomen sein könnte und diskutieren, warum dieses Verhalten anfitness-relevante Parameter gekoppelt sein sollte. Um welche es sich dabei handeln könnte, wurde bisher nicht hinreichend untersucht und muß deshalb offen bleiben.
    Notizen: Summary Carrion Crow and Hooded Crow are regarded as subspecies of the Crow. They show frequent hybridisation along the adjacent borders of their distribution. Mixed pairs produce fertile offspring which are able to breed successfully with both hybrids and mates of either phenotype. However, hybridisation does not lead to phenotypic changes of Carrion and Hooded Crows in general nor in their distinct distribution. We studied the mating behaviour of Crows in the hybrid zone on the Island of Amrum (Schleswig-Holstein, Germany) and found evidence that Crows may prefer mates of the same phenotype. Our data confirm previous studies which reported assortative mating with respect to plumage coloration from hybrid zones in Italy and Siberia. We discuss why this behaviour should be related tofitness traits which in our opinion have not yet been studied adequately nor identified.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 98
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 88 (1998), S. 81-96 
    ISSN: 1570-7458
    Schlagwort(e): chlorogenic acid ; Heliothis virescens ; Manduca sexta ; Pseudoplusia includens ; rutin ; Spodoptera frugiperda ; temperature ; tomatine ; Trichoplusia ni
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Analysis of the combined effects of allelochemicals on insect herbivores is useful because there may be adverse additive or even synergistic effects. Analysis of the simultaneous effects of temperature and alleochemicals is also necessary because these factors may interact. We examined the effects of three allelochemicals found in tomato (chlorogenic acid, rutin and tomatine) and thermal regime (21:10 °C and 26:15 °C, representing spring and summer respectively) on five insect herbivores (a Solanaceae specialist, Manduca sexta, and the polyphagous Heliothis virescens, Pseudoplusia includens, Spodoptera frugiperda and Trichoplusia ni). There were allelochemical interactions and thermal regime-allelochemical interactions for all species, and so the patterns were complex. In some cases, paired allelochemicals or the combination of three allelochemicals showed adverse additive effects on insect performance. But that was not always the case, and there were only a few examples of synergism. Negative effects of the allelochemicals were sometimes, but not always, damped by the cooler thermal regime. Comparing the growth rates of the five species in this study with those of a previous study (a total of seven species) revealed five patterns. For two of three pairs of closely-related species, the paired species had distinctly different patterns. For example, for H. virescens, tomatine prevented development and chlorogenic acid slowed growth, whereas for Helicoverpa zea, tomatine just slowed growth and the phenolics had little effect. The specialist Manduca sexta had a pattern that was midway between patterns of the generalists; it was not the most tolerant of the allelochemicals.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 99
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 86 (1998), S. 13-24 
    ISSN: 1570-7458
    Schlagwort(e): Drosophila ; cytoplasmic incompatibility ; Wolbachia ; temperature ; antibiotics ; density
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effects of high temperatures, antibiotics, nutrition and larval density on cytoplasmic incompatibility caused by a Wolbachia infection were investigated in Drosophila simulans. Exposure of larvae from an infected stock to moderate doses of tetracycline led to complete incompatibility when treated females were crossed to infected males; the same doses only caused a partial restoration of compatibility when treated males were crossed to uninfected females. In crosses with treated females, there was a strong correlation between dose effects on hatch rates and infection levels in embryos produced by these females. Ageing and rearing males at a high temperature led to increased compatibility. However, exposing infected females to a high temperature did not influence their compatibility with infected males. Male temperature effects depended on conditions experienced at the larval stage but not the pupal stage. Exposure to 25 °C reduced the density of Wolbachia in embryos compared with a 19 °C treatment. Low levels of nutrition led to increased compatibility, but no effect of larval crowding was detected. These findings show the ways environmental factors can influence the expression of cytoplasmic incompatibility and suggest that environmental effects may be mediated by bacterial density.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 100
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 86 (1998), S. 49-58 
    ISSN: 1570-7458
    Schlagwort(e): aphids ; Sitobion ; population ; chromosomal race ; mean relative growth rate ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Chromosomal races of the aphid Sitobion miscanthi (Takahashi), and a closely-related species S. near fragariae (Aphididae: Macrosiphini) show seasonal differences in abundance in eastern Australia. We tested whether this was related to differences in temperature response, using controlled laboratory conditions. Intrinsic rate of increase, rm, mean relative growth rate (MRGR), and longevity were compared at different temperatures, and rates of increase were compared outdoors under ambient conditions. Using laboratory data, we simulated population growth, for comparison with outdoor populations. There were significant differences in responses to temperature regimes both in the laboratory and outdoors. Outdoor populations fell well short of predicted sizes. S. miscanthi (2n=18) showed evidence of adaptation to warmer conditions. In contrast, S. nr fragariae showed consistent evidence for adaptation to cooler conditions, and S. miscanthi 2n=17 was approximately intermediate. These data indicate that temperature responses are important in the ecology, evolution and pest status of S. miscanthi clones and S. nr fragariae in Australia.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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