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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 80 (1996), S. 481-489 
    ISSN: 1570-7458
    Keywords: reproductive compatibility ; hybrid inviability ; temperature ; Trichogramma ; biological control ; Hymenoptera ; Trichogrammatidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In non-reciprocal cross-incompatibility (NRCI), the crossing of a female of a strain A with a male of a strain B results in hybrid offspring, whereas the reciprocal cross produces few or no hybrids. Only females are of hybrid origin in Hymenoptera because they arise from fertilized eggs; males arise from unfertilized (haploid) eggs. Crosses between many strains of Trichogramma deion showed some degree of NRCI. Crosses between a T. deion culture collected in Seven Pines, California (SVP) with one from Marysville, California (MRY) showed an extreme form of NRCI in which practically no female offspring was produced when MRY females were crossed with SVP males. The reciprocal cross produced a close to normal proportion of female and male offspring. Detailed studied of this cross indicated that 1) the female offspring produced in the compatible interstrain cross were not the result of parthenogenesis but were true hybrids, 2) the incompatible interstrain cross did not produce female offspring because fertilized eggs died during development, 3) the death of these eggs could not be prevented by either antibiotic or temperature treatment, 4) cytoplasmically inherited factors causing NRCI could be discounted because backcrossed females with the genome of MRY and the cytoplasm of SVP, exhibit the NRCI relationship characteristic of their genome. Therefore the NRCI between these strains appears to be caused by a modification coded for by the nuclear genes of MRY that results in incompatibility when SVP sperm fertilizes MRY eggs. In addition the level of incompatibility in crosses between the SVP females and MRY males is temperature sensitive, the higher the rearing temperature the lower the level of compatibility.
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  • 2
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    Entomologia experimentalis et applicata 85 (1997), S. 231-236 
    ISSN: 1570-7458
    Keywords: Glossina fuscipes fuscipes ; vegetation ; biconical trap ; temperature ; light ; relative humidity ; monitor lizard
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Glossina fuscipes fuscipes Newstead was sampled in isolated thickets and forest patches near Lake Victoria, Kenya using unbaited biconical traps, between March 1992 and June 1993. Traps set at 1 m from the forest edge caught 3.3 times as many males and 5 times as many females as those set inside or 10 m away. The corresponding figures at 1 m from the edge of thicket were about 1.43 and 1.64 times, respectively. Hourly catches of males and females were positively correlated with temperature, light intensity and host (monitor lizard) prevalence, and negatively correlated with relative humidity. Light intensity and temperature were the most important variables affecting the catches of each sex. The results are discussed in relation to control and monitoring of G. f. fuscipes using traps.
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  • 3
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    Entomologia experimentalis et applicata 80 (1996), S. 511-519 
    ISSN: 1570-7458
    Keywords: sweet potato whitefly ; temperature ; relative humidity ; migration and dispersal ; virus transmission ; Homoptera ; Aleyrodidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The ability of the sweet potato whitefly, Bemisia tabaci Gennad., to survive a range of environmental conditions was investigated in the laboratory. The range of temperature and humidity investigated corresponds to the normal climatic range during B. tabaci's summer migration in Israel. Adult whiteflies confined to small test cages were exposed to combinations of temperature (25, 30, 35, and 41 °C) and relative humidity (20, 50, 80, and 100%) for periods of 2, 4, or 6 h. A logistic regression model describing the four-dimensional surface defining percent survival as a function of time, temperature, and humidity was developed. Using stepwise regression to exclude non-significant terms, the linear predictor included temperature, and the products of temperature and time, and humidity and time. The model accounted for 75% of the variance. A reparameterization of the fitted regression model suggests that survival potential is conditioned by temperature conditions prevailing during the previous 10 h. Whitefly survival after 2 h exposure ranged from ≈ 90% survival at 20°C and 100% RH, to 〈2% survival at 41°C and 20% r.h.. No whiteflies survived more than 2 h exposure at these latter extremes of temperature and humidity. Survival rates decreased slightly after experimental whiteflies were kept in a cage with food a further 20 h at 25±2°C, 55±5% r.h. Investigations of the effects of hunger and virus infection, showed that both increased mortality.
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  • 4
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    Entomologia experimentalis et applicata 83 (1997), S. 171-180 
    ISSN: 1570-7458
    Keywords: within-plant heterogeneity ; tent caterpillars ; temperature ; circular statistics ; Lepidoptera ; Yponomeutidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The caterpillars of Yponomeuta mahalebella Latr. (Lepidoptera: Yponomeutidae) are monophagous on Prunus mahaleb (Rosaceae) leaves. Adult females deposit eggs in batches, which determines larval gregarious behaviour. Coupled with gregarious behaviour, caterpillars spin silk tents within they will feed until pupation. Distribution of tents in the field, their effect in microenvironmental larval growth conditions and the consequences for adult body mass and survival of larvae were studied. There was a significant trend for tents to be placed with a southward orientation. Within-plant tent orientation was related to the sun-shade pattern experienced, which was the main effect determining thermal differences between the inside and the outside of the tent. These differences appeared to affect larval growth and survival, with higher survival of larvae and heavier adults emerging from tents oriented to the south-east and east, respectively.
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  • 5
    ISSN: 1572-8099
    Keywords: point of fire origin ; fire ; temperature ; plaster ; concrete ; thermal ; damage ; biotite ; magnetization ; susceptibility ; N-rays ; P-rays ; X-rays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract Magnetic susceptibility (MS) measurements were taken to determine fire exposure patterns on noncombustible structural members and compartment boundaries. These measurements led on-site fire investigators to the cause of combustion and the point of fire origin. Thermal damage to walls and to ceilings was estimated quantitatively by measuring MS and two-valent Fe ion concentration in building materials such as concrete and plaster. It was shown that these effects are preconditioned by thermochemical transformations in the mineral biotite, which is present as a component of common building materials. For the first time, the effect of a substantial and irreversible increase in biotite magnetization exposed to powerful flows of N- and P-rays was found. It is hoped that the presence of this “magnetic trace” of radiation in building materials will allow investigators to use the magnetometric method at nuclear power plant catastrophes such as that in Chernobyl. It was also shown that the influence of N- and P-rays on biotite's magnetic properties greatly differs from the thermal influence on biotite.
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  • 6
    ISSN: 1570-7458
    Keywords: Amblyseius cucumeris ; Frankliniella occidentalis ; rate of predation ; temperature ; vapor pressure deficit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The influence of temperature and vapor pressure deficit (VPD) on the rate of predation by the predatory mite, Amblyseius cucumeris (Oudemans) on Frankliniella occidentalis (Pergande) was determined under controlled laboratory conditions. The survival of first instars of F. occidentalis was initially determined by themselves. Then the number of first instars that were killed by a single female adult of A. cucumeris was determined for the same density of thrips. The differences in the mortality between the two experiments were used to calculate the rate of predation by A. cucumeris under a range of temperature and VPD regimes. Rate of predation was expressed as the number of thrips killed per h to account for the different time periods that the trials lasted. A quadratic model was fitted to the data. At a constant temperature, the rate of predation decreased with increasing VPD for VPDs 〈-1.24 to 1.44 kPa. Above these VPDs, the rate of predation started to increase again. At a constant VPD, the rate of predation decreased slightly at the lower temperatures and increased at the higher temperatures. The rate of change was dependent upon the VPD. By using the quadratic model, the rate of predation can be predicted for the range of hygrothermal conditions that would be encountered in the greenhouse. The optimal condition for maximum rate of predation by A. cucumeris on first instars of F. occidentalis in the greenhouse is a VPD 〈- 0.75 kPa at the recommended production temperatures and VPDs (17 to 25°C and 〈- 1.5 kPa).
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  • 7
    ISSN: 1570-7458
    Keywords: cowpea ; Vigna unguiculata ; pod sucking bugs ; age-specific life tables ; temperature ; insect development ; cohort statistics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Age-specific life tables of two important pests of cowpea, Vigna unguiculata (L.) Walp., the pod sucking bugs Clavigralla tomentosicollis Stål and C. shadabi Dolling (Heteroptera: Coreidae), were obtained from observations carried out at different temperatures. A biophysical model was found satisfactory to describe the temperature-response of developmental and mortality rates of egg and nymphal stages, with a peak developmental rate around 34°C in both species. The variability in development times was small and the experimental data did not permit any conclusion with regard to the Erlang probability density function. Survival of eggs and nymphs remained high between 20° and 30°C for both species. At temperatures above 34°C, C. tomentosicollis survivorship and fecundity was higher than that of C. shadabi, which in turn laid more eggs at temperatures between 20° and 30°C. Maximum fecundity is estimated to be at 29°C for C. tomentosicollis (99 eggs/female) and 26°C for C. shadabi (261 eggs/female). At 30°C, the intrinsic rate of increase reached a maximum in both species, 0.152 per day for C. tomentosicollis and 0.145 per day for C. shadabi, and remained high for C. tomentosicollis until 36°C. C. tomentosicollis performed significantly better on pigeonpea, Cajanus cajan Millsp., than on cowpea at higher temperatures.
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  • 8
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    Entomologia experimentalis et applicata 82 (1997), S. 159-166 
    ISSN: 1570-7458
    Keywords: Diaeretiella rapae ; reproduction ; life-tables ; temperature ; Diuraphis noxia ; biological control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Diaeretiella rapae (M'Intosh), a polyphagous and cosmopolitan parasite of aphids, was imported from China to the USA for biological control of Diuraphis noxia (Mordwilko), a pest of small grains. We studied several aspects of its biology on D. noxia hosts in the laboratory at 3 constant temperatures, 10.0, 21.1, and 26.7 °C. Females lived significantly longer than males at all 3 temperatures, and longevity was greatest at 10 °C, followed by 21.1 and 26.7 °C. Fecundity (= number of mummies) did not differ significantly among the 3 temperatures studied. The ovarian egg-load was 129.1 ± 9.3, and was significantly affected by the size of adult females. A pre-oviposition period ± 0.26 days) was detected at 10 °C, but not at the other temperatures. Pre-imaginal survivorship was similar among temperatures, while R o and T c decreased with temperature, and r m increased with temperature. The offspring sex ratio (proportion females) was lowest at 26.7 °C, and similar between 10.0 and 21.1 °C. In addition, the offspring sex ratio significantly declined with the age of the female parent. The suitability of D. rapae for colonization against D. noxia in North America is discussed in relation to its responses to temperature and the climate of its home range.
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  • 9
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    Entomologia experimentalis et applicata 82 (1997), S. 319-333 
    ISSN: 1570-7458
    Keywords: chlorogenic acid ; light availability ; Lycopersicon esculentum ; Manduca sexta ; protein ; rutin ; temperature ; tomatine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We examined how light availability influenced the defensive chemistry of tomato (Lycopersicon esculentum: Solanaceae). Tomato plants were grown either in full sunlight or under shade cloth rated at 73%. Leaves from plants grown in full sunlight were tougher, had higher concentrations of allelochemicals (chlorogenic acid, rutin and tomatine), and had less protein than leaves from plants grown in shade. We determined how these differences in host plant quality due to light availability affected the behavior and growth of a Solanaceae specialist, Manduca sexta. Both in the greenhouse and in the field, caterpillars on shade-grown plants grew heavier in a shorter amount of time than those on plants that had previously been grown in full sunlight. In contrast, the effects of previous light availability to plants on caterpillar behavior appeared to be minor. To further investigate how light availability to plants influenced herbivore growth, we examined the effects of leaf-powder diets made from tomato leaves of different ages (new, intermediate, or mature) grown in full sunlight or shade on caterpillar performance. Caterpillars fed diets made from plants grown in shade consumed less but grew faster than larvae fed diets made from tomato plants grown in full sunlight. Caterpillars fed diets made from new leaves grew larger in less time than caterpillars fed diets made from intermediate aged leaves. Caterpillars did not survive on the mature leaf powder diets. There were plant-light treatment by larval thermal regime interactions. For example, at 26:15 °C , plant-light treatment had no effect on stadium duration, but at 21:10 °C, stadium duration was prolonged with the full sunlight-new leaf diet compared with the shaded-new leaf diet. In a second diet experiment, we examined the interactive effects of protein and some tomato allelochemicals (rutin, chlorogenic acid and tomatine) on the performance of caterpillars. There were food quality by thermal regime interactions. For instance, at 26:15 °C , neither protein nor allelochemical concentration influenced stadium duration, whereas at 21:10 °C, stadium duration was prolonged with the low protein-high allelochemical diet, which simulated full sunlight leaves. In sum, light availability to plants affected defensive chemistry and protein concentration. The difference in food quality was great enough to influence the growth of a specialist insect herbivore, but the effects were temperature-dependent.
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  • 10
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    Entomologia experimentalis et applicata 84 (1997), S. 255-265 
    ISSN: 1570-7458
    Keywords: Delia radicum ; postdiapause development ; temperature ; Diptera ; Anthomyiidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Canadian populations of D. radicum differ in their response to temperature during postdiapause development. Populations that are primarily of the early-emerging type ( $$\left( { \leqslant 256DD_{04} } \right)$$ ) (St-Jean, Quebec; London, Ontario) have high values for the parameters describing this response: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOuamaaBa% aaleaacaWGTbaabeaakiabg2da9aaa!38F2!$$R_m = $$ 12.7–13.3; $$T_m = $$ 28.0–31.8 °C ; Tσ = 10.3–14.2 ( $$R_m $$ , the maximum developmental rate at the temperature, $$T_m $$ [ °C ] where the developmental rate is highest, and Tσ , the parameter which gives the shape of the truncated normal curve fitted to the data), a low degree-day requirement for emergence (160–232 $$DD_{04} $$ ), and may lack a developmental delay at temperatures above ca. 21 °C . Populations of the late-emerging type (Kildare, Prince Edward Island) have low parameter values ( $$ R_m = 2.5$$ , $$T_m = 19.3$$ °C ; Tσ = 6.4), high degree-day requirements (530 $$DD_{04} $$ ), and a developmental delay at high temperatures. The parameters for the early-emergers in the population from Winnipeg, Manitoba (74% early) were intermediate ( $$R_m = 9.1$$ , $$T_m = 27.1$$ °C , Tσ = 10.7, $$ DD_{04} = 246 $$ ), but resembled the early rather than the late type. This population varied from 31 to 90% early type over a 10-year period and the rate of postdiapause development at 20 °C was directly related to the percentage early. In the year with the most rapid development (90% early), development was significantly slower than in the populations from other locations with predominantly early populations, and the year with the slowest development (31% early) showed significantly faster development than that from Kildare, Prince Edward Island (100% late). Therefore the parameters for early and late types of development will not be accurate for use in mixed populations, and the parameters in mixed populations will change among years. Populations of D. radicum in North America and Europe (67 locations by years) varied from 0–100% early. At Winnipeg, the percentage early was directly related to the annual temperature accumulation ( $$DD_{05} $$ ) during the growing season. The calculation of developmental parameters for the early-emergers of mixed populations provides a more accurate basis for estimating the times of first emergence and the first peak of emergence than parameters based on the whole population. Since postdiapause developmental rates vary both among and annually within locations, developmental models should be designed to include such variations.
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  • 11
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    Entomologia experimentalis et applicata 79 (1996), S. 9-17 
    ISSN: 1570-7458
    Keywords: Anthonomus pomorum ; temperature ; diel cycle ; Coleoptera ; Curculionidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Individual pairs of overwintered adult apple blossom weevils, Anthonomus pomorum (L.), confined with apple twigs under different ambient temperatures in the laboratory and on apple trees in the field, were observed through day and night for their spring activities. Flight behavior in relation to ambient temperature was also investigated under laboratory conditions using flight stands. Both sexes displayed predominantly nocturnal behavior patterns in both the laboratory and the field. Feeding, crawling, and mating activities increased following sunset in the field or onset of scotophase in the laboratory while resting occurred most frequently during daylight hours. Results of the laboratory experiments showed that temperature affected significantly the activity patterns. The diel pattern of activities became less distinctive at higher temperatures (above 15°C), and total activities in crawling, feeding, and mating were suppressed significantly at lower temperatures (below 5°C). Over 97% of the test weevils initiated take-off response from flight stands at 20°C within the 30 min trial period; however, flight initiation rarely occurred at temperatures 12°C or below. Overall, results of the laboratory and field experiments indicate that A. pomorum is a remarkably cold-adapted insect with ability to crawl, feed, and mate at a few degrees above freezing, a physiological attribute necessary for the exploitation of early stages of apple bud development in the cold early spring.
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  • 12
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    Entomologia experimentalis et applicata 80 (1996), S. 461-468 
    ISSN: 1570-7458
    Keywords: Trichogramma minutum ; Choristoneura fumiferana ; Ephestia kuehniella ; biological control ; inundative release ; weather ; host acceptance ; realized fecundity ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of weather conditions and two parasitoid quality attributes, realized fecundity and host acceptance, were assessed on the field efficacy of mass-released Trichogramma minutum. Temperature was the most important single variable, explaining up to 75% of the variation in field parasitism. There were significant positive relationships between both the sum of the maximum temperatures and the number of degree-hours above a 15 °C threshold, accumulated in the three days following the release, and parasitism in the field. There was a significant negative relationship between the mean relative humidity and the odds of parasitism in the field. Quality parameters based on parasitoid biology were not effective for predicting field efficacy if poor weather conditions persisted after a release. If weather conditions were ‘good’ (i.e. accumulated maximum temperatures above 62 °C, in the 3 days following the release), then parameters such as release rate and fecundity in the lab were useful predictors of field performance. There was no relationship between host acceptance measured in the lab and field parasitism. Given the importance of field temperatures for field performance, selection for cold tolerance of T. minutum would be desirable.
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  • 13
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    Journal of applied electrochemistry 27 (1997), S. 1328-1332 
    ISSN: 1572-8838
    Keywords: metal hydride ; capacity ; temperature ; performance ; enthalpy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The effect of temperature on the performance of a LaNi4.76Sn0.24 metal hydride electrode was investigated in the temperature range of 0 to 50°C. The electrode showed a maximum discharge capacity at 25°C. The total resistance increases with a decrease of temperature from 50°C to 0°C. The apparent activation enthalpies at different states of charge were determined by evaluating the polarization resistance at different temperatures. It was found that the apparent activation enthalpy is an indicator of the relative reaction rate of the charge-transfer reaction and hydrogen absorption.
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  • 14
    ISSN: 1572-8773
    Keywords: cadmium ; copper ; iron ; photoperiod ; temperature ; zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The importance of photoperiod and ambient temperature on the accumulation of cadmium in the liver and kidneys of bank voles was determined in the present study. Males and females, aged 1 month, were given 3.0 μg Cd ml−1 drinking water and divided into four groups according to photoperiod (16 h light/8 h dark and 8 h light/16 h dark) and ambient temperature (20 or 5°C); liver and kidneys were removed for cadmium as well as copper, iron and zinc analyses at the end of 6 weeks. Bank voles exposed to 5°C in both photoperiods consumed approximately 30% less water containing cadmium than those kept at 20°C. However, the total accumulation of cadmium in the liver and kidneys of males and females exposed to the low temperatures was 4.3–4.8 and 2.2–3.3 times less than that in animals maintained at room temperature in the long and short photoperiod, respectively. Simultaneously, the low temperature brought about an increase in the copper concentrations in the liver (12–43%) and kidneys (47–78%), giving rise to an inverse correlation between the cadmium accumulation and the tissue copper concentration. In contrast to cadmium and copper, the concentrations of iron and zinc were affected primarily by photoperiod. These findings indicate that ambient temperature is an important determinant of cadmium retention in the bank vole. It appears that low temperature decreases tissue cadmium accumulation not only by reducing cadmium intake but also through changes in copper metabolism.
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  • 15
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    Journal of solution chemistry 25 (1996), S. 711-729 
    ISSN: 1572-8927
    Keywords: Conductivity ; aqueous ; sodium hydroxide ; ion association ; temperature ; pressure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The limiting molar conductances Λ0 and ion association constants of dilute aqueous NaOH solutions (〈0.01 mol-kg−1) were determined by electrical conductance measurements at temperatures from 100 to 600°C and pressures up to 300 MPa. The limiting molar conductances of NaOH(aq) were found to increase with increasing temperature up to 300°C and with decreasing water density ρw. At temperatures ≥400°C, and densities between 0.6 to 0.8 g-cm−3, Λ0 is nearly temperature-independent but increases linearly with decreasing density, and then decreases at densities 〈0.6 g-cm−3. This phenomenon is largely due to the breakdown of the hydrogen-bonded, structure of water. The molal association constants K Am for NaOH( aq ) increase with increasing temperature and decreasing density. The logarithm of the molal association constant can be represented as a function of temperature (Kelvin) and the logarithm of the density of water by $$\begin{gathered} log K_{Am} = 2.477 - 951.53/T - (9.307 \hfill \\ - 3482.8/T)log \rho _{w } (25 - 600^\circ C) \hfill \\ \end{gathered} $$ which includes selected data taken from the literature, or by $$\begin{gathered} log K_{Am} = 1.648 - 370.31/T - (13.215 \hfill \\ - 6300.5/T)log \rho _{w } (400 - 600^\circ C) \hfill \\ \end{gathered} $$ which is based solely on results from the present study over this temperature range (and to 300 MPa) where the measurements are most precise.
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  • 16
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    Archive of applied mechanics 67 (1997), S. 331-338 
    ISSN: 1432-0681
    Keywords: Key words frictional heating ; wear ; contact pressure ; temperature ; brake system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary A transient contact problem with frictional heating and wear for two nonuniform sliding half-spaces is considered. One of the two half-spaces is assumed to be slightly curved to give a Hertzian initial pressure distribution: the other is a rigid nonconductor. Under the assumption that the contact pressure distribution could be described by Hertz formulas during all the process of interaction, the problem is formulated in terms of one integral equation of Volterra type with unknown radius of contact area. A numerical solution of this equation is obtained using a piecewise-constant presentation of an unknown function. The influence of operating parameters on the contact temperature and the radius of the contact area is studied.
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  • 17
    ISSN: 1573-0417
    Keywords: palaeolimnology ; acidification ; diatoms ; chrysophytes ; pigments ; chironomids ; temperature ; Alps ; Italy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract A palaeoecological study of an oligotrophic alpine lake, Paione Superiore (Italy), provided a record of historical changes in water quality. Historical trends in lake acidification were reconstructed by means of calibration and regression equations from diatoms, chrysophycean scales and pigment ratios. The historical pH was inferred by using two different diatom calibration data sets, one specific to the alpine region. These pH trends, together with the record of sedimentary carbonaceous particles and chironomid remains, indicate a recent acidification of this low alkalinity lake. Concentration of total organic matter, organic carbon, nitrogen, biogenic silica (BSiO2), chlorophyll derivatives (CD), fucoxanthin, diatom cell concentration and number of chironomid head capsules increased during the last 2–3 decades. When expressed as accumulation rates, most of these parameters tended to decrease from the past century to c. 1950, then all except P increased to the present day. A marked increase in sedimentary nitrogen may be related to atmospheric pollution and to the general increases in output of N in Europe. High C/N ratios indicate a prevailing allochthonous source of organic matter. Finally, the increase in measured air temperature from the mid-1800's appeared to be related to lake water pH before industrialization: cold periods generally led to lower pH and vice-versa. The more recent phenomenon of anthropogenic acidification has apparently decoupled this climatic-water chemistry relationship.
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  • 18
    ISSN: 1573-0832
    Keywords: Anthracnose ; guava ; Colletotrichum glososporioides ; temperature ; free moisture ; inoculum density
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The influence of environmental factors (temperature and humidity), inoculum density on infection by Colletotrichum glososporioides and development of anthracnose lesions were determined on uninjured, sand-injured and punctured fruits. The optical temperature for severe infection was 30 °C, whereas the disease incidence was less at 20 and 35 °C. Inoculated guavas that received 1–60 h of continuous free moisture developed lesions, but the disease was minimal (0–7%) after 1–6 h free moisture. Infection rates of uninjured, sand-injured and punctured fruits receiving 60 h of free moisture were 34, 70 and 100%, respectively. Disease incidence increased as inoculum density increased from 101 to 106 conidia/ml. In field conditions, the development of anthracnose lesions was greater on punctured guavas than on uninjured or sand-injured ones, in both rainy and winter seasons. In general, the number of lesions was highest in sand-injured fruits, followed by punctured and uninjured fruits. In rainy season the number of lesions on injured and uninjured fruits was greater than similarly treated guavas in winter.
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  • 19
    ISSN: 1573-0832
    Keywords: Antagonism ; biocontrol ; ginger ; postharvest rot ; Sclerotium rolfsii ; Trichoderma ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Sclerotium rolfsii is a destructive soil-borne and postharvest plant pathogen. Use of the antagonistic fungus Trichoderma sp. has been earlier reported by us to successfully control this pathogen under postharvest conditions. In the present paper we report on the effects of temperature on the growth and biocontrol potential of Trichoderma sp. on S. rolfsii. Experimental results indicated that S. rolfsii and Trichoderma sp. have different temperature optima for growth: 30–35 °C for the pathogen and 25–30 °C for the antagonist. In dual culture, Trichoderma overgrew S. rolfsii at 25 °C and 30 °C, but at 35 °C and 37 °C, S. rolfsii overgrew the colony of Trichoderma. Trichoderma produced higher concentration of fungitoxic metabolites in broth culture at higher temperatures. In bioassays using ginger slices and whole rhizomes, it has been demonstrated that Trichoderma is not very effective in suppressing S. rolfsii at temperatures above 30 °C. In light of these results, possible mechanisms of biocontrol of S. rolfsii as a postharvest pathogen has been discussed. Storage temperature has been suggested as a critical factor in biocontrol of S. rolfsii.
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  • 20
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    Mycopathologia 136 (1996), S. 109-114 
    ISSN: 1573-0832
    Keywords: Fungi ; post-harvest rot ; relative humidity ; temperature ; Vitex doniana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The fungi associated with rot of Vitex doniana fruits (blackplum) were isolated and identified. Aspergillus niger, Botryodiplodia theobromae, Candida spp. Penicillium chrysogenum, Rhizopus stolonifer, Fusarium pallidoroseum F. oxysporum and Mucor mucedo were the primary rot causing fungi in contrast to Cladosporium herbarum and Mucor circinelloides which were just present as secondary colonizers. The rot fungi penetrated mainly through wounds and bruises on the surface of fruits. Mature green fruits were less susceptible to infection than half ripe and fully ripened red fruits. Optimum rot by pathogenic isolates occurred at 25–30 °C and relative humidity 72.5–100%. The results of investigation of influence of storage temperatures and relative humidity on the quality of uninoculated healthy fruits are presented and discussed.
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  • 21
    ISSN: 1573-0867
    Keywords: heavily fertilized soils ; P supplying capacity ; P uptake ; residual P ; soil test methods ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Nine heavily fertilized soils were collected from southern and central Norway. A greenhouse experiment in the phytotron was conducted to evaluate the P supplying capacities of these soils at different temperatures (9, 12 and 18 °C). The crops were grown in succession and the sequence was oat, rye grass (cut twice), oat, rape and oat. Effect of temperature on dry matter (DM) yield and P uptake was more marked up to the fourth crop but the effect varied among crops. The DM yields of oat and rape increased with increasing temperature but the opposite was the case with rye grass. The yield differences among soils at 12 °C were highly significant (p 〈 0.01) in contrast to 9 and 18 °C. The amount of P taken up by plants in these soils was highest at 18. °C. The P supplying capacity was highest in the soils with higher content of organic P. Generally, the soils of very fine and coarse texture classes failed to supply enough P to crops to avoid P deficiency in the successive crops. Soil P test (P-NH4-lactate) values in most of the soils increased with increasing temperatures. The highest temperature effect was seen in the Særheim sand soil. Soil P test extractants P-AL, Bray-1 and Colwell-P were used to determine P in the soil after each harvest and the soil P test values were compared with P uptake by crops. Only the P-AL extractant was significantly correlated to cumulative P removal (CPR) by plants in most of the soils. Regression equation was calculated for each soil. The value of removed P per harvest (RPH) varied from 10.33 to 20.87 mg P kg−1 soil. Phosphorus drawdown slope was determined for each soil and the number of consecutive harvests necessary to reduce the P-AL value to a normal level (110 mg P kg−1 soil) was calculated. The drawdown slope varied widely (1.257–2.801) and this reflected the P buffer capacity and the number of crops required to lower the soil test P value to a normal level. The highest drawdown slope was found in the soils with higher P supplying capacities. The Bray-1 extractant was significantly correlated in the soils with higher buffer capacity but the Colwell-P method did not show significant correlation in any of the soils.
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  • 22
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    Nutrient cycling in agroecosystems 46 (1996), S. 179-187 
    ISSN: 1573-0867
    Keywords: electrical conductivity ; leaching ; nitrogen ; pH ; phosphorus ; potassium ; release pattern ; slow-release fertilizers ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We studied the effect of temperature on the release of N, P, and K from slow-release fertilizers (SRF). The study was conducted in micro-lysimeters filled with moist peat medium. Increasing the temperature from 4 to 12°C slightly increased N release from three different slow-release N (SRN) carriers with different particle sizes and coating thicknesses. At 21°C the rate of release was significantly different than the other two temperatures. Urea formaldehyde (UF), sulphur coated urea (SCU) and coated calcium nitrate (CCN), incubated in sphagnum moss peat, released between 3 and 20% of the applied N in six weeks. For eight synthetic and organic NPK carriers, the release pattern was similar to UF and SCU. However, the leaching losses of N from the NPK fertilizers were up to twenty times more than for the SRN products. Except for Osmocote® and Duna, which released 30–40% of the applied N as mineral-N within six weeks, all other slow-release and slowly mineralized NPK carriers acted like readily water-soluble compound NPK. Temperature did not affect the nutrient release from NPK fertilizers.
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  • 23
    ISSN: 1573-0832
    Keywords: Entomopathogenic hyphomycete ; Paecilomyces fumosoroseus ; inoculum persistence ; solar radiation ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The detrimental effect of solar radiation on the survival of conidia of the entomopathogenic fungusPaecilomyces fumoroseus was studied by monitoring germinability and ability to form colonies (CFU) of conidia irradiated at two temperatures, 25 and 35 °C, harmless to shaded conidia. There was no apparent effect when spores were exposed to a high level of artificial radiation (0.66 W m−2 UVB). However, at a lower level of irradiance (0.33 W m−2), effects of radiation occurred more quickly at 35 °C than at 25 °C. Under natural solar radiation, the rate of decrease in germinability or viability was doubled at 35 °C as compared to 25 °C, indicating an interaction between temperature and radiation effects under natural conditions. This interaction was not detected in indoor experiments, indicating that the spectral distribution of UV radiation has to be taken in account as well as its irradiance when studying its effects.
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  • 24
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    Surveys in geophysics 17 (1996), S. 289-306 
    ISSN: 1573-0956
    Keywords: Effective properties ; pore fluids ; cracked rock ; permeability ; stress ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Fluids saturating cracked rocks within the crust can vary widely in composition and physical properties, which depend greatly on pressure and temperature. External non-hydrostatic stress applied to a cracked medium may result in a significant change of crack volume (and hence, for the undrained regime, pore-fluid pressure) due to the processes of crack closure (opening), and thus lead to a drastic change of the overall physical parameters of a rock. The purpose of the study is to estimate theoretically, using the effective-medium theory, the macroscopic seismic and transport parameters (such as permeability) of cracked rocks (granites) saturated with hydrocarbon gases, oils, brines and water. Variations of crack geometry and fluid parameters in the closed system (at constant fluid mass) under uniaxial compression are considered as well. The results show that composition of a saturating fluid as well as fluid temperature greatly influence the effective permeability and shear velocities of a rock mass, while thermal conductivity is not so sensitive to variations of fluid parameters.
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  • 25
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    Nutrient cycling in agroecosystems 47 (1996), S. 19-28 
    ISSN: 1573-0867
    Keywords: elemental sulphur ; model ; oxidation rate ; particle size distribution ; soil ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Finely-powdered elemental sulphur is a useful source of fertilizer S, being readily oxidizable in soil to plant-available sulphate yet possessing some slow release characteristics. Two mesh sizes were evaluated using four soils from northeast Scotland. Particle size analysis found that the 120 and 300 mesh S samples had specific surface areas of 1300 and 1940 cm2 g−1, respectively, with most of the surface area in particles of 10 – 20 µm diameter. The S oxidation rate was similar in all four soils but was greater for the 300 mesh than for the 120 mesh S: mean values of 51% and 18% were oxidized over 7 weeks at 14 °C, respectively. The time course of oxidation followed a sigmoidal pattern with a pronounced lag which was modelled using the logistic equation. Maximum specific oxidation rates were 11–28 µg S cm−2 day−2 for the 300 mesh S at 14 °C. These were significantly slower at 7 °C and the temperature response was calculated as a Q10 of 4.0. A model of seasonal S oxidation was developed using a cosine function for the annual temperature, the Arrhenius equation to relate S oxidation rate to temperature and a generalization of the logistic equation to describe the time course of S oxidation. Simulations showed that the 300 mesh S would be useful for spring S applications in east Scotland and if applied in autumn could supply S during the autumn and again in the spring. The 120 mesh S would be less effective in autumn but more resistant to winter leaching. The 120 mesh S applied to the warmer soils of southwest England would behave the same as 300 mesh S applied in east Scotland.
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  • 26
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    Journal of statistical physics 85 (1996), S. 471-488 
    ISSN: 1572-9613
    Keywords: Electron-phonon interaction ; temperature ; polaron ; Holstein model ; bifurcation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract It is proved that the polaronic and bipolaronic structures found in the adiabatic Holstein model at large electron-phonon coupling by Aubry, Abramovici, and Raimbault survive under connection of the electrons to a low-temperature heat bath, uniformly in the size of the system. Bounds are computed for one-dimensional nearest neighbor chains, and some sample solutions are continued numerically.
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  • 27
    ISSN: 1432-072X
    Keywords: Key words Anaerobic sulfate reduction ; Incomplete ; propionate oxidation ; Marine environment ; Low ; temperature ; Psychrophilic bacteria ; Growth yields ; Desulforhopalus vacuolatus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new type of gas-vacuolated, sulfate-reducing bacterium was isolated at 10° C from reduced mud (E0 〈 0) obtained from a temperate estuary with thiosulfate and lactate as substrates. The strain was moderately psychrophilic with optimum growth at 18–19° C and a maximum growth temperature of 24° C. Propionate, lactate, and alcohols served as electron donors and carbon sources. The organism grew heterotrophically only with hydrogen as electron donor. Propionate and lactate were incompletely oxidized to acetate; traces of lactate were fermented to propionate, CO2, and possibly acetate in the presence of sulfate. Pyruvate was utilized both with and without an electron acceptor present. The strain did not contain desulfoviridin. The G+C content was 48.4 mol%. The differences in the 16S rRNA sequence of the isolate compared with that of its closest phylogenetic neighbors, bacteria of the genus Desulfobulbus, support the assignment of the isolate to a new genus. The isolate is described as the type strain of the new species and genus, Desulforhopalus vacuolatus.
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  • 28
    ISSN: 1440-1703
    Keywords: double cropping field ; soil respiration ; temperature ; water content
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Carbon dioxide evolution rates from a double cropping, upland rice and barley field were determined in central Japan from June 1992 to May 1994, and regression models were developed to predict soil respiration rate. Diurnal patterns of hourly soil respiration rates (SRh) showed a similar trend with those of soil surface temperatures. Daily soil respiration rate (SRd) obtained by integrating SRh varied from 0.3 to 15.6 g CO2 m−2 for the 2 years. In the summer cropping period, SRd was positively correlated with daily mean soil surface temperature and negatively correlated with volumetric water content in soil. Moreover, this relationship was able to be expressed as a multiple-factor model with an Adj-R2 of 0.925. On the other hand, in the winter cropping period, SRd was able to be represented by a single factor model using soil surface temperature with an Adj-R2 of 0.854. Based on these relationships, seasonal changes in soil respiration rate were estimated. Total soil respiration rates in 1992 and 1993 estimated for the summer cropping period were 1260 g CO2 m−2 and 1094 g CO2 m−2, and for the winter cropping period 624 g CO2 m−2 and 676 g CO2 m−2, respectively. It was considered that the lower values during the summer cropping period in 1993 depended on lower soil surface temperature and higher soil water content.
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  • 29
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    Journal of thermal analysis and calorimetry 49 (1997), S. 857-862 
    ISSN: 1572-8943
    Keywords: analytical methods ; kinetics ; powder milk ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract This work present comparative results on powder milk storage quality, obtained from analytical methods. Protein content was determined conventional (Kjeldahl) and colorimetric with biuret reagent at 540 nm and integral quality by thermogravimetric and biological methods. A method was developed for the protein separation of powder milk. Powder milk was submitted to degradation processes at 45, 60 and 80°C for 20 days. The results indicated that protein content values were inconsistent if determinations by Kjeldahl and colorimetric methods and biological tests were compared. There is evidence of thermal decomposition of powder milk as detected by biological and thermogravimetric methods.
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  • 30
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    Journal of nondestructive evaluation 16 (1997), S. 91-100 
    ISSN: 1573-4862
    Keywords: LASER ultrasound ; anisotropic material ; group velocity ; stiffness coefficients ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract Ultrasonic waves are generated through a composite material by means of a noncontact technique. It uses a Nd:Yag LASER for the generation and an interferometric probe for the detection of acoustic waveforms. From a suitable set of experimental data, an inversion scheme is used for the recovering of four stiffness coefficients. They characterize the elasticity in a principal plane of symmetry of the material which exhibits an orthorhombic symmetry. The measurements are performed at various temperatures, elevated by steps up to 300°C for two specimen. The sensitivity of the method appears convenient to measure the temperature induced stiffness changes. The anisotropic degradation of the material properties are then pointed out.
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  • 31
    ISSN: 1573-2932
    Keywords: Acidic deposition ; vesicular-arbuscular mycorrhizae ; seedling nutrition ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Accumulation of reducing sugars (i.e., glucose and fructose) in plant roots has been consistently correlated with forest dieback and decline and, therefore, has potential as a biological indicator of ecosystem stress. In this study, the relationships between acidic deposition and “natural” (temperature, mycorrhizae, and nutrition) factors with first-year sugar maple seedling root sugar concentrations and growth were assessed in two sugar maple dominated forests in Michigan. Seedlings at the southern site (Wellston) had greater root growth, phosphorus, total sugar, and sucrose concentrations in roots, but lower reducing sugar concentration in roots. In addition, percent root length colonized by vesicular-arbuscular mycorrhizal fungi was less than that found for seedlings growing at the northern site (Alberta). Throughfall deposition of nitrate, sulfate, and hydrogen ions was not significantly correlated with seedling total or reducing sugar concentration. Total sugar concentration in seedling roots was positively correlated with air and soil temperatures at the southern site, but not at the northern site. Seedling tissue phosphorus concentration was correlated with total sugars at both sites, with sucrose at the southern site, and reducing sugars at the northern site. Mycorrhizal colonization rates at the Alberta site were positively correlated with reducing sugar concentration in seedling roots and negatively correlated with sucrose concentration. The results suggest that differences in seedling root sugar concentrations in these two forests are related to seedling root growth and are most likely due to ecological variables, such as available soil phosphorus, temperature, and growing season length through some complex interaction with mycorrhizae rather than acidic deposition stress.
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  • 32
    ISSN: 1871-4528
    Keywords: skin resistance ; temperature ; Solanum tuberosum L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Chambers were designed to simulate environmental conditions present in commercial potato stores and were used to introduce condensation to tubers infected with silver scurf (Helminthosporium solani). The electrical resistance measured across the skin of tubers from the top of the chambers was consistently lower than that from the bottom of the chamber, and this was reflected in an increased number ofH. solani spores produced by the top tubers. An increase in the length of the condensation period resulted in the skin resistance remaining lower for a longer period and also resulted in higher number of spores. Tubers held at relatively high ambient temperatures (15 °C) required a shorter period of condensation to cause an increase in spore count. This investigation highlighted the need for close monitoring of store environments so that condensation events can be quickly identified and the tubers dried.
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  • 33
    ISSN: 1871-4528
    Keywords: light ; temperature ; stolon growth medium ; below ground nodes ; Solanum tuberosum L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Five experiments studied the effects of shading, temperature and stolon growth medium on stolon and tuber formation. The lowest numbers of stolons and tubers were produced at the higher and lower nodes. Numbers of primary stolons and tubers were relatively stable across nodes and treatments and variation in total numbers was largely due to changes in numbers of lateral and branch stolons. In the field, 70% shading reduced numbers of stolons and tubers by reducing lateral and branch stolons, while in hydroponics, 45% shading and temperatures at initiation had no effect on tuber numbers. In both environments later planting tended to reduce numbers of stolons and tubers. There were large effects of the physical environment, with compost producing three times as many tubers as dry vermiculite. The potential number of tubers may be determined by the number of stolons and the environmental conditions affecting stolon formation and development.
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  • 34
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    Potato research 39 (1996), S. 581-607 
    ISSN: 1871-4528
    Keywords: assimilate partitioning ; flower primordia survival ; flower production ; photoperiod ; stem production ; temperature ; time to flower primordia initiation ; tuber initiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The shoot system of potato is a configuration of stems with terminal inflorescences. In this review, shoot development is quantified in terms of stem production, while stem development is quantified in terms of leaf and flower primordia production per stem, which are functions of the rates and the durations of primordia initiation. The effect of the position of the stem in the shoot system on number of leaves and flowers per stem is also evaluated. Flowering of individual stems is described by the ‘time to flower primordia initiation’ (expressed in number of leaves produced) and ‘flower production’ (a function of the number and the development of flower primordia). At warmer temperatures and longer daylengths the number of leaves and flower primordia per stem, and the number of stems per shoot increase by prolonging stem production and primordia development. Temperature and photoperiod also affect flower primordia survival by altering assimilate production and partitioning. The photothermal response of the number of leaves per stem is small compared to the response of stem production; at higher temperatures, flower primordia survival becomes the principal factor determining flower production. The similarity of the signals leading to flower primordia initiation and tuberization, and the relation between shoot and tuber growth are discussed.
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  • 35
    ISSN: 1618-2545
    Keywords: pH ; Saprolegnia diclina ; Saprolegnia parasitica ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Saprolegnia diclina andS. parasitica isolated from three sources could germinate in strong acidic conditions. Growth ability correlated with the species of fungi rather than with the sources from which they were isolated.S.diclina isolates appeared to germinate at a pH condition as low as 3.5, whereasS. parasitica isolates could not germinate at below pH 3.8.S. parasitica isolates from visceral mycoses still showed good growth at 30°C, whereas other isolates did not. Also,S. parasitica isolates from visceral mycoses produced more abundant motile zoospores, and continued to do so for a longer period of time (28 d), thanS. parasitica isolates from external saprolegniasis andS. diclina isolates.
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  • 36
    ISSN: 1573-5125
    Keywords: Dreissena polymorpha ; byssus thread production ; temperature ; salinity ; agitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Byssus thread production ofD. polymorpha under different conditions of temperature, salinity and agitation were studied in the laboratory. The acclimation to salinity and temperature greatly affects the byssus production ofD. polymorpha. Byssus production of mussels was significantly reduced when temperature increased beyond 20°C and decreased below 10°C. Mussels with cut threads (for counting), produced a substantially increased number of threads. However, mussels with uncut byssus threads were comparatively more mobile. Byssus production of mussels did not vary significantly at salinities up to 3‰. Beyond this salinity byssus production was reduced significantly. Mussels increased their byssus production with increasing frequency of agitation.
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  • 37
    ISSN: 1573-5176
    Keywords: fluorescence ; photoinhibition ; photosynthesis ; Spirulina ; photobioreactor ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A chlorophyll fluorescence technique was applied to anin situ study on the effects of low temperature and high light stresses onSpirulina cultures grown outdoors in controlled tubular photobioreactors at high (1.1 g L−1) and low (0.44 g L−1) biomass concentrations. Diurnal changes in PSII photochemistry (F v/F m) after 15 min of darkness, or in the light (dF/F′ m), and non-photochemical (qN) quenching were measured using a portable, pulse-amplitude-modulated fluorometer. The depression of theF v/F m ratio ofSpirulina cultures grown outdoors at 25°C (i.e. 10°C below optimum for growth) and 0.44 g L−1, reached 30% at the middle of the day. At the same time of the day thedF/F′ m ratio showed a reduction of up to 52%. The depression of bothF v/F m anddF/F′ m was lower in the cultures grown at 1.1 g L−1. Photoinhibition reduced the daily productivity of the culture grown at 0.44 g L−1 and 25°C by 33% with respect to that grown at 35°C. Changes in the growth yields of the cultures grown under different temperatures and growth rates correlate well with analogous changes in photon yield (dF/F′ m). Simple measurements of photochemical yield (F v/F m) can be used to test the physiological status ofSpirulina cultures. The results indicate that the saturating pulse fluorescence technique, when usedin situ, is a powerful tool for assessment of the photosynthetic characteristics of outdoor cultures ofSpirulina.
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  • 38
    ISSN: 1573-5176
    Keywords: Arthrospira platensis ; Spirulina ; tubular photobioreactors ; outdoor culture ; aeration rate ; cell density ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Arthrospira (Spirulina) platensis M2 was grown outdoors in 50-mm diameter tubular reactors under the climatic conditions of central Italy (Florence) from September to December 1995 and in March 1996. Except for September, the cultures temperature was regulated. Mean productivities of 0.83, 0.44 and 0.61 g dry wt L−1 d−1 were achieved in autumn (September–October), winter (November–December) and March, respectively. In autumn and winter, the photosynthetic efficiency of the cultures and the degree of correlation between productivity and solar irradiance were significantly greater than in summer. The effect of cell density and aeration rate on productivity was evaluated in September. The productivity of cultures operated at high supra-optimal population density was about 30% less at high aeration rate (1.0 LL−1 min−1), and 50% less at standard aeration rate (0.17 LL−1 min−1), than that of control cultures kept at optimal population density and standard aeration rate. The reduction of productivity in high-density cultures was due to lower daylight output rates and higher night biomass losses (the latter were particularly relevant under standard aeration conditions). The main factor limiting productivity in closed reactors during autumn was the night temperature. Heating the cultures during daylight hours on sunny days did not cause any significant increase of the yields, since under sunlight the unheated cultures also reached the optimal temperature for growth early in the morning. On cloudy days, the day-time temperature of the unheated cultures remained well below the optimum, however this had only a limited effect on productivity since algal growth was mainly light-limited.
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  • 39
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    Mycoscience 38 (1997), S. 135-140 
    ISSN: 1618-2545
    Keywords: Aphanomyces frigidophilus ; morphology ; pH ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Aphanomyces frigidophilus sp. nov. was obtained from eggs of Japanese char,Salvelinus leucomaenis, from Tochigi Prefectural Fisheries Experimental Station, Utsunomiya, Japan. Vegetative hyphae were delicate, slightly wavy, moderately branched. Zoosporangia were isodiametric with the vegetative hyphae. Oogonia were abundant, originating on short stalks from lateral sides of hyphae. Oogonia were spherical, subspherical or pyriform, with a single subcentric oospore inside. Outer surfaces of oogonia were roughened with short papillate, crenulate or irregular ornaments. Antheridia and oospore germination were not observed. Zoospore germination and vegetative growth were found from pH 5.0 to 11.0. Zoospore production was highest at 10°C, whereas rapid growth occurred at 20–25°C. Vegetative growth of the fungus declined from the maximal level at 25°C to less than half maximal at 30°C and completely disappeared at 35°C.
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  • 40
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    Journal of applied phycology 9 (1997), S. 269-276 
    ISSN: 1573-5176
    Keywords: Fucus distichus ; polar day ; trace metals ; light ; temperature ; tide ; rhythms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Variation of Mn, Fe, Ni, Cu and Zn contents in thalli of Fucus distichus was determined under conditions of polar days. The use of spectrum analysis allowed estimates comparisons of the interrelation of periodic changes in irradiance, temperature and tidal fluctuations and quasiperiodic changes in metal contents. The effect of the diel rhythm of irradiance correlated with the accumulation of all metals except for Zn. At the same time, the changes in Mn, Fe and Cu content were delayed in respect to changes in irradiance level. The phase shift for Fe was 1 h 56 min, for Cu – 3 h 41 min and for Mn – 5 h5 min. The change in Ni content, in contrast, was 11min ahead of the change in irradiance. During the experiment an increase in water temperature up to10 °C resulted in increases in the average Mn, Ni and Cu contents in the thalli and decreases in Fe and Zn concents. The periodicity of metal thallus content did not always correspond to a diurnal rhythm, and couldbe longer (Mn, Ni: 32 h; Fe: 36 h) or shorter (Mn, Ni, Zn: 16 h; Cu: 12 h; Zn: 20, 10 h). The ANOVA of these rhythms allows an estimate of the contribution of rising and falling tidal fluctuations to the changes in Cu, Mn and Ni contents. There was a higher metal content during a falling than a rising tide. Abbreviations SDLT – semidiurnal lunartide, CDLT – closed diurnal lunar tide.
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  • 41
    ISSN: 1573-5176
    Keywords: Antarctic ; Arctic ; cyanobacteria ; green algae ; mass algal culture ; Phormidium ; temperature ; waste-water treatment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Forty-nine strains of filamentous, mat-forming cyanobacteria isolated from the Arctic, subarctic and Antarctic environments were screened for their potential use in outdoor waste-water treatment systems designed for cold north-temperate climates. The most promising isolate (strain E18, Phormidium sp. from a high Arctic lake) grew well at low temperatures and formed aggregates (flocs) that could be readily harvested by sedimentation. We evaluated the growth and nutrient uptake abilities of E18 relative to a community of green algae (a Chlorococcalean assemblage, denoted Vc) sampled from a tertiary treatment system in Valcartier, Canada. E18 had superior growth rates below 15°C Canada. (µ = 0.20 d-1 at 10°C under continuous irradiance of 225 µmol photon m-2 s-1) and higher phosphate uptake rates below 10°C (k = 0.050 d-1 at 5°C) relative to Vc (µ=0.087 d-1 at 10°C and k = 0.020 d-1 at 5°C, respectively). The green algal assemblage generally performed better than E18 at high temperatures (at 25°C, µ = 0.39 d-1 and k = 0.34 d-1 for Vc; µ = 0.28 d-1 and k = 0.33 d-1 for E18). However, E18 removed nitrate more efficiently than Vc at most temperatures including 25°C. Polar cyanobacteria such as strain E18 are appropriate species for waste-water treatment in cold climates during spring and autumn. Under warmer summer conditions, fast-growing green algae such as the Vc assemblage are likely to colonize and dominate, but warm-water Phormidium isolates could be used at that time.
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  • 42
    ISSN: 1573-5176
    Keywords: Arthrospira (Spirulina) platensis ; integrated culture system ; raceway pond ; photobioreactor ; alveolar panel ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cultivation of microalgae in closed photobioreactors suffers from high temperatures, whereas in open raceway ponds the optimal temperature is seldom reached. With an integrated device coupling a raceway pond with a suitably sized and positioned closed system (alveolar panel), the heat accumulated in the panel was efficiently transferred to the pond and a near-optimum temperature regimen for Arthrospira platensis was maintained, with no need for any additional cooling device. The productivity obtained in the integrated system was higher than the sum of the productivities (g reactor−1 day−1) of the pond and panel systems operating separately.
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  • 43
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    Journal of applied phycology 9 (1997), S. 229-236 
    ISSN: 1573-5176
    Keywords: nutrients ; growth rate ; Hydrodictyon reticulatum ; seasonal changes ; temperature ; growth prediction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Since Hydrodictyon reticulatum was introduced to New Zealand it has spread rapidly and produced persistent annual nuisance growths in areas where nuisance algal had not occurred previously. Field bioassays were conducted at 10 sites between August 1993 and February 1995 to evaluate the seasonal growth patterns and the factors controlling growth under natural conditions. H. reticulatum exhibited a strong seasonal growth pattern with growth rates up to 0.33 doublings d-1 from August to March, are duction in growth rate in April and little or no growth from May to July. The H. reticulatum present in New Zealand has are latively low requirement for dissolved inorganic nitrogen (DIN) in comparison with other nuisance species, with its growth rate being saturated at 200 mg m-3. This and the high affinity for DIN as shown by a Ks of 29 mg m-3 have been key factors in the establishment of nuisance growths of H. reticulatum in New Zealand.
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  • 44
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    Journal of applied phycology 9 (1997), S. 451-457 
    ISSN: 1573-5176
    Keywords: Isochrysis galbana ; lipid ; biochemical composition ; fatty acid ; temperature ; growthphase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The lipid and biochemical composition of the haptophyte Isochrysis galbana TK1 was examined. Cultures were grown at 15 °C and 30 °C, and harvested in the exponential and early stationary growth phases. Carbohydrate and protein content varied at the two culture temperatures and growth phases. The highest protein content was found at the exponential growth phase at 15 °C, and the highest carbohydrate content was found at the stationary phase at the same culture temperature. Lipid accumulated in the stationary growth phase and its content was higher at 30 °C than at 15 °C regardless of the growth phase. The neutral lipids were the major class of lipid found in all the cultures. The stationary phase culture had a higher proportion of neutral lipids than the exponential phase culture and the proportion decreased slightly when culture temperature was increased from 15 °C to 30 °C. Phospholipid levels remained constant at the two temperatures, but slightly decreased in the stationary phase. Glycolipids in the exponentially growing cells were higher than those from stationary growth phase and increased with temperature. Polyunsaturated fatty acids (PUFAs) predominated in glycolipids and phospholipids. Cells grown at 15 °C contained higher proportion of 18:3 (n–3) and 22:6 (n–3) with a corresponding decrease in 18:2 (n–6), monounsaturated and saturated fatty acids.
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  • 45
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    Biodiversity and conservation 5 (1996), S. 1505-1523 
    ISSN: 1572-9710
    Keywords: seasonal changes ; benthic bacteria ; bacterioplankton ; bacterial communities ; organic matter ; temperature ; Antarctic Oceans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: A short overview of the biodiversity of Antarctic marine bacteria is given with respect to morphology and metabolic activity. The importance of spatial and temporal variability is described. The physiological adaptation and ecological function of Antarctic marine bacterioplankton are discussed.
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  • 46
    ISSN: 1573-5125
    Keywords: toxicity ; cyanobacteria ; zooplankton ; population growth ; temperature
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    Topics: Biology
    Notes: Abstract The ability of cladocerans and rotifers to utilise the cyanobacterium Microcystis aeruginosa was tested by comparing the somatic and population growth in cultures using Chlorella and Microcystis as food types. Five species of cladocerans (Ceriodaphnia cornuta, Scapholeberis kingi, Moina macrocopa, Daphnia carinata, Simocephalus vetulus) and two species of rotifers (Brachionus calyciflorus, Hexarthra mira) were used in this study. In order to exclude the possibility of poor utilisation of Microcystis due to mechanical interference, single cells of Microcystis, (obtained by sonicating large colonies) were also offered. Experiments were done at 20 °Cs and 30 °C . In all the treatments tested, the population growth rate per day of the cladocerans ranged from -0.715 to 0.612 and that of the rotifers from -1.15 to 0.781. While C. cornuta, S. kingi and S. vetulus could utilise Microcystis, M. macrocopa and D. carinata were extremely susceptible to its toxins. The ability of the cladoceran populations to grow on Microcystis single cells was not related to the body length or gut length alone but to their ratio. The toxic effects of Microcystis were mitigated at the higher temperature. A strain of C. cornuta, collected from a Microcystis-dominated lake, had a higher growth rate on the toxic cyanobacteria suggesting that the tolerance to Microcystis could be a heritable trait. Of the two rotifer species, only H. mira survived and reproduced in some treatments of Microcystis.
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  • 47
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    Journal of applied phycology 9 (1997), S. 175-178 
    ISSN: 1573-5176
    Keywords: callus cells ; chloroplast ; differentiation ; Eckloniopsis radicosa ; Laminariales ; light intensity ; Phaeophyta ; temperature ; tissue culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Excised rectangular blade pieces of young sporophytes of Eckloniopsis radicosa (Kjellman) Okamura were cultured at four different temperatures (10, 15, 20, 25 °C) and light intensities (10, 20, 40, 80 µmol photon m−2 s−1) to observe callus cell propagation and differentiation. Although rapidly propagating callus cells were observed at a low temperature (15 °C) and low light intensities of (10–20 µmol photon m−2 s−1), differentiation to bladelets was only observed at higher temperatures and light intensities. In rapidly propagating callus cells, the chloroplasts decreased in both size and number. When callus cells with few chloroplasts were exposed to high temperature and light intensity, the chloroplasts gradually increased in number and size until they were the same size as found in cells from young blades. Finally, these cells differentiated and produced bladelets. This is the first report describing a relationship between differentiation and chloroplast size and number in the callus cells on E. radicosa.
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  • 48
    ISSN: 1573-5117
    Keywords: insects ; seasonality ; photoperiod ; temperature ; developmental reactions ; modelling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A great body of knowledge of photoperiodic and other developmental reactions, governing seasonality in insects, may be helpful for similar investigations which are or will be conducted with other animal groups. The following principles, based on a recent hypothesis, seem the most significant to be tested in comparative studies. (1) On the level of the photoperiodic clock only quantitative perception of photoperiod takes place. (2) The following, presumably neuroendocrine, ‘managing’ level of the mechanism discriminates between long and short days, determines the type of the response, and integrates photoperiodic and temperature reactions. (3) A working hypothesis, to be tested with both insects and other invertebrates, is that the ‘managing’ mechanism described in the model of photoperiodic and temperature control of development may have several sensory inputs and, therefore, plays a central role in governing developmental reactions to different environmental cues.
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  • 49
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    Hydrobiologia 320 (1996), S. 191-196 
    ISSN: 1573-5117
    Keywords: harpacticoids ; diapause ; temperature ; Lake Ladoga
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The spatial distribution of Canthocamptus staphylinus (Jurine) in Lake Ladoga was examined. C. staphylinus is one of the most numerous species of harpacticoids in the lake. It can dwell in almost all littoral biotopes. In profundal biotopes strongly exposed to anthropogenic influence (pollution and eutrophication) only this species of harpacticoid was found. A peculiarity of C. staphylinus biology is that in summer individuals are in the resting stage as cysts. In summer active individuals were found in littoral habitats at a water temperature of 20 °C, but their number was small in comparison with cold periods of the year. In the littoral zone the relative number of individuals in cysts was clearly related to water temperature. Twelve degrees temperature appears to be critical for development of littoral populations of C. staphylinus.
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  • 50
    ISSN: 1573-5117
    Keywords: sediments ; method ; organic matter ; difference-on-ignition ; weight ; temperature ; time
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract For the routine determination of organic matter inmarine sediment, a rough estimate is often obtained bymeasuring the loss of weight on ignition(Difference-On-Ignition method: D.O.I.). This D.O.I. is to beused in ecological studies where organic material insediment is used as an environmental variable amongothers. A review of papers using this method showed agreat variability within conditions used. Theseconditions are generally used without accuratejustification. We propose a simple standard procedurebased on grain-size fraction of sediment to determineoptimal temperature and time of ignition, and theinfluence of the sample weight. The method proposed, using the loss of weight on ignition, will give thesame accuracy in measurements of organic matter inmarine sediments.
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  • 51
    ISSN: 1573-5117
    Keywords: microcrustacean zooplankton ; tropical limnology ; laboratory cultures ; growth ; development rates ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Length growth, instar durations, fecundity and mortality rates of fivespecies of microcrustacean zooplankton from a tropical reservoir weremeasured in relation to food quantity and temperature in laboratorycultures. Three cladocerans (Ceriodaphnia cornuta, Moina micrura,Diaphanosoma excisum), one calanoid copepod (Heliodiaptomus viduus), and onecyclopoid copepod (Mesocyclops thermocyclopoides) were studied. Filteredseston (45 µm mesh) from a local pond was used for food. Two foodconcentrations were employed: (1) 10 µg chlorophyll l−1(ca 0.25 mg Cl−1), and (2) 50 µg chlorophylll−1 (ca 1.25 mg C l−1). Food levels and watertemperature (22.5, 27.5, and 32.5 °C) used, roughly covered the rangesfound in the reservoir. Although all the three growth parameters were oftenaffected to some degree by temperature and food, the quantitative responseof the species differed. Also, the species reacted differently to the threepossible interactions (i.e. food × temperature,food × instar, andtemperature × instar). This contributed to the overalldifferences in the species responses. For the cladocerans, instar durationswere always affected by temperature. The food did not affect the durationtime of the adults and that of the combined juvenile instars, the latterexcept in one case significantly. For the two copepods food level affectedthe duration times of naupliar and copepodite instars, but the effect oftemperature was only significant for H. viduus. The development timesobserved for H. viduus were extraordinary long compared with values reportedin the literature for other tropical calanoids. This suggests that foodconditions in our culture were adversely affecting its growth rates.
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  • 52
    ISSN: 1573-5117
    Keywords: weedbed ; growth ; physiology ; pH ; oxygen ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In slow-moving and static eutrophic waters, submerged macrophytes growing in dense stands produce a highly structured environment, with reduced internal water flow. An afternoon lull in the net photosynthesis of such stands has been reported from a number of previous studies. This has been attributed to increased photorespiration caused by an accumulation of photosynthetically-derived, dissolved oxygen in the surrounding water. Results here demonstrate that even in a water quite rich in dissolved inorganic carbon (2.5 mmol l−1), limitations on the supply of inorganic carbon will normally be more important in curtailing photosynthesis, with photorespiration playing only a minor role.
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  • 53
    ISSN: 1573-5117
    Keywords: rotifers ; Brachionus plicatilis ; Brachionus rotundiformis ; energy content ; chemicalcomposition ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of temperature on the chemical composition (carbon, nitrogenand ash content) and the energy content of the rotifers Brachionusplicatilis and Brachionus rotundiformis (formerly B. plicatilis L- andS-type respectively) was examined in experimental populations. Dry weightand carbon, nitrogen and hydrogen content remained practically unchanged inthe 20–35 °C range in B. rotundiformis, while in B.plicatilis the dry weight decreased slightly with increasing temperaturefrom 15 ° to 35 °C. Nevertheless, themajor source of variation was the fecundity status of the populations. Onthe other hand, B. rotundiformis showed higher energy content (joules per mgof dry matter) than B. plicatilis. This difference in energy content was dueto the different ash content because the organic matter of both species hadthe same energy content, as well as the same basic biomass composition.
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  • 54
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    Hydrobiologia 364 (1997), S. 199-208 
    ISSN: 1573-5117
    Keywords: Phytoplankton ; photosynthesis ; light ; temperature ; tidal freshwater ; irradiance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The photosynthetic response to irradiance wasquantified for phytoplankton from the tidalfreshwater Potomac River biweekly to monthly over aperiod of six years. Samples were collected from twoshallow embayments and portions of the deeper rivermainstem. Photosynthetic rate was measured in thelaboratory at in situ temperature over a range ofirradiance levels and photosynthetic parameters werecalculated using nonlinear regression.PB max,the maximum photosynthetic ratestandardized to chlorophyll a, increased withtemperature up to 25 °C with a Q10 of 2.02. Above 25 °C, PB max was essentiallyconstant with temperature. Lesser correlationbetween PB max and ambient irradiance couldbe explained by the correlation of irradiance withtemperature. α, the slope of the P–I curve atlow light, was correlated with both ambientirradiance and temperature. Highest α valueswere found in late summer when high temperature andintermediate ambient irradiance were observed. Spring and early summer were characterized by lowα. Despite low light penetration, Ik andα values were indicative of sun limitationpossibly due to intermittent high light levelsexperienced during mixing. Ik showed a clearseasonal trend directly related to days from summersolstice. Spatial patterns were minimal except thatIk was consistently lower in one shallowembayment than in the other two areas. Seasonalpatterns in photosynthetic parameters correspondedroughly to changes from a spring diatom populationto summer cyanobacterial assemblage.
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  • 55
    ISSN: 1573-5117
    Keywords: Chaoborus ; energetics ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chaoborus, the phantom midge (Insecta, Diptera, Chaoboridae), has a widespread distribution, commonly occurring in lakes and ponds all over the world. In the great lakes region of East Africa Chaoborus is present in Lakes Victoria, Albert, Edward, Malawi and George, but absent from Lakes Tanganyika, Kivu and Turkana. Tropical lakes typically have water temperatures in the range of 22–26 °C year round. Lakes Tanganyika and Kivu have only 20% of their bottom sediments oxygenated during full circulation, contrary to 95–100% in all of the other lakes, excluding Lake Malawi (45%) (Hecky & Kling, 1987). Planktivorous fish are present in all lakes (Lehman, 1995). We hypothesized that the absence of Chaoborus larvae from some lakes of East Africa may be the result of interaction among high temperatures, low oxygen levels, and fish predation. We developed a model to estimate energetic costs for Chaoborus larvae at temperatures greater than 14 °C. We hoped to shed light on the bioenergetics of Chaoborus populations, and the possibility that extant distributions of Chaoborus larvae are the result of energetic constraints. We found that relative respiratory and growth costs of Chaoborus larvae are highest in the early stages of development. We estimated that non-feeding instar I larvae living in 25 °C water will starve to death in less than one day. It is possible that Chaoborus populations are prevented from establishing in certain areas because high energetic costs condemn young larvae to death by either predation or starvation.
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  • 56
    ISSN: 1573-8469
    Keywords: monocyclic process ; epidemiology ; UV B ; temperature ; Uncinula necator ; Vitis vinifera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Conidia ofUncinula necator inoculated on vine leaf disks were exposed to different irradiation conditions during various combinations of irradiation periods. In controlled experiments at constant leaf temperature spore germination and mycelial growth were negatively affected by the UV B doses, irrespective of the exposition duration. In semi-controlled condition experiments, conidia were exposed to shaded, sunny and sunny without UV B radiation conditions. Shaded conditions were always more favourable to spore germination and mycelial growth than sunny conditions. Under two different ranges of temperature (20–24 and 26–31 °C for shaded conditions), the effect of radiation on germination and mycelial growth differed. Thus, the effect of radiation on spore germination and mycelial growth seems to be affected by temperature. In general, radiation effects increased as the number of exposition periods increased, indicating that both spore germination and mycelial growth were reduced, but not totally stopped by the different exposures. Germination was most affected by exposures applied just after inoculation, whereas mycelial growth was most affected by exposures applied one day after inoculation. These results indicate that radiation is an important factor to consider for a better understanding of the relationships between climate and grape powdery mildew epidemics.
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  • 57
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    European journal of plant pathology 103 (1997), S. 573-580 
    ISSN: 1573-8469
    Keywords: Pisum sativum ; host plant exudates ; light ; temperature ; infection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effects of host plant exudates, light and temperature on germination of oospores of Peronospora viciae f.sp. pisi in vitro were investigated. Seed and root exudates did not increase percentage germination, whereas light inhibited germination. The first germ tubes appeared after 4, 7, and 14 days of incubation at 15, 10 and 5 °C, respectively. The eventual level of germination was highest and had similar values at 5 and 10 °C. At 20 °C germination was poor and at 25 °C no germination was observed. Oospores placed on membrane filters were incubated on soil. When oospores were retrieved from the membrane filters after six days and placed in water at 10 °C, they germinated within 2 days. On soil significantly less oospores germinated than in water. Germinability of oospores stored in the dark at 5 or 20 °C at 30 or 76% RH was studied over a two-year period. Germinability generally increased over time, but fluctuations were observed indicating the occurrence of secondary dormancy. Time courses of germinability were generally similar for oospores stored at several temperatures and humidities. No effect of light on time course of germinability was found when oospores were exposed to alternating light-dark periods or stored in continuous dark for 140 days. Percentage germination observed in a germination assay was correlated with percentage infection determined in a bioassay.
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  • 58
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    Colloid & polymer science 275 (1997), S. 467-473 
    ISSN: 1435-1536
    Keywords: Key words Block copolymers ; micelle ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract  The association behaviour of triblock copoly(ethylene oxide/tetrahydrofuran/ethylene oxide), in particular E100T27E100, in aqueous solutions has been investigated by means of static and dynamic light scattering, nuclear magnetic reso-nance (NMR) and surface tension techniques. On raising the polymer concentration at room temperature, the copolymer aggregates to form micelles with an aggregation number of about 105 (R G, mic≈15 nm and R H, mic≈13 nm, as revealed by light scattering and FT-PGSE NMR measurements, respectively). The micelles are kinetically quite stable, the micellar lifetime is shown to be more than 1 h. The residence time of a single unimer in a micelle is more than 140 ms. The apparent radius of gyration R G, mic is fairly independent of concentration, but large effects are observed on varying the temperature. Raising the temperature initially results in an increase of the apparent micellar size, followed by a maximum at an intermediate temperature (≈45 °C). At higher temperatures a contraction of the micelles is observed. The shape of the micelles also appear to vary in this temperature interval. The interactions responsible for these phenomena are discussed in terms of, e.g., the temperature-dependent solubility of the alkylene oxide segments in water and polydispersity effects.
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  • 59
    ISSN: 1573-5060
    Keywords: drought ; flowering ; grain yield ; pearl millet ; Pennisetum glaucum ; temperature ; water satisfaction index
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Throughout much of the semi-arid tropics, fluctuations in grain yield can largely be attributed to differences in timing and intensity of drought stress. Since seasonal rainfall in these environments is often poorly related to grain yield, the aim of this paper was to establish a relationship between water availability and grain yield for pearl millet (Pennisetum glaucum (L.) R. Br.), grown across 24 semi-arid tropical environments in India. We used a simple soil water budget to calculate a water satisfaction index (WSI) throughout the season. The cumulative WSI at maturity explained 76% of the variance in grain yield. This was three times as much as explained by actual rainfall, because WSI accounted for differences in water losses and pan evaporation. A classification of environments into four groups of water availability patterns explained 75% of the environmental sum of squares for grain yield. For a subset of 13 environments, environmental differences in grain number could also be explained by water availability patterns, whereas differences in grain mass were related to both water availability and temperature. Our results indicate that cumulative WSI, which is an integrated measure of plant-available water, can provide an adequate estimation of the environmental potential for yield in environments where grain yield is mainly limited by variable availability of water.
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  • 60
    ISSN: 1573-5060
    Keywords: escape ; genotype-by-environment interaction ; pearl millet ; Pennisetum glaucum ; soil water availability, stress ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Grain yields in drought-affected environments are often characterized by large genotype-by-environment (GE) interactions, caused by a highly variable timing and intensity of stress occurrence. The aim of our study was to assess the effectiveness of simple meteorological environmental descriptions in providing an understanding of the environmental contribution to the GE interaction of pearl millet (Pennisetum glaucum (L.) R. Br.) in the semi-arid tropics. The experiment comprised fourteen genotypes, grown across 24 environments in India. Data on water availability throughout the season and maximum temperatures during grain filling were used to describe the environments. Escape from drought and heat stress were the major factors determining the GE interaction. Both the timing and intensity of stress occurrence were important. Knowledge of the environmental causes of the GE interaction may facilitate the identification of adaptive plant traits, and may also enable a more rational choice of test locations for breeding programs.
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  • 61
    ISSN: 1573-5060
    Keywords: seed orchard ; phenology ; frost hardiness ; environmental preconditioning ; temperature ; photoperiod ; Norway spruce ; Picea abies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Several independent tests have shown that climate and weather during sexual reproduction influence the adaptive properties of the Picea abies progenies. This phenomenon is expressed in seed orchards established by moving parent trees, propagated as grafts, from north to south, from high to low elevation, or from outdoor to indoor greenhouse conditions. The progenies exhibit delayed flushing in the spring, later growth cessation of leader shoots in the summer, delayed bud-set, higher frequency of lammas shoots and delayed development of frost hardiness in the autumn compared to progenies reproduced in the colder native environment. The altered performance is persistent. We have found no effect on progenies of photoperiod and temperature treatments given to the males during meiosis and pollen production. However, when crosses were made in early spring (March), inside a heated greenhouse (short day, high temperature), the progenies are less frost hardy during cold acclimation than progenies from identical crosses performed in late spring (May; long day high temperature) in the greenhouse. The most hardy offspring were from crosses performed under outdoor conditions in May (long day, low temperature). These results indicate that some stages in reproduction, such as female meiosis, pollen tube growth, syngamy and early embryo development, are sensitive to temperature and/or photoperiod which then alter the phenotypic performance of the offspring. The most likely explanation is the existence of a regulatory mechanism affecting the expression of genes controlling adaptive traits. If this is true, it must have implications for the genetic interpretation of provenance differences in Norway spruce.
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  • 62
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    Euphytica 92 (1996), S. 235-239 
    ISSN: 1573-5060
    Keywords: acclimatization ; adaptation ; annual rhythm ; diversity ; photoperiod ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Many cultivated crop plants of temperate and cool temperate zones have during their domestication been transferred far from their original habitats and been distributed over a wide range of climates. In general crop plants seem to possess potential to climatic adaptation. Processes in the past have taken hundreds or thousands of years and over large number of generations. The concern on the velocity of the expected global warming and of subsequent changes in other factors justifies planning of breeding for global warming. Perennial plants, forest trees in particular are more at the focal point than annual plants. Most agricultural annuals may be replaced any year with another cultivar or species better adapted to contemporary circumstances. Trees need tens of years to reach commercial dimensions or fructiferous age. Capriciousness is the main problem of climate change. Large variation of temperature, precipitation among years actually masks the gradual change of average values. The amplitude of variation among years exceeds the predicted average change. Thus, plasticity of individuals besides within population variation in adaptive traits is a corner stone of breeding plans. From the ecological point of view two factors are significant: 1. mild winters may interfere dormancy release and frost tolerance, and also alter host-parasite relationships. 2. The timing of thermal seasons will change in relation to photoperiod. This phenomenon is most prominent in the far north, where the relative warming is largest and the photoperiodic pattern steepest. Even though perennial plants display potential of acclimatization, selection and breeding are eligible measures to improve productivity. As long as the magnitude and velocity of the global warming remain uncertain, it is impossible to set specified aims to breeding. The only reasonable method is to run parallelly several lines with differing patterns of adaptive traits. Multiple population breeding system (MPBS) seems to be tailored to this purpose.
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  • 63
    ISSN: 1573-5036
    Keywords: catch crop ; mineralisation ; nitrogen ; simulation model ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The release of nitrogen from incorporated catch crop material in winter is strongly influenced by soil temperatures. A laboratory experiment was carried out to investigate this influence in the range of 1-15 °C. Samples of sandy soil or a mixture of sandy soil with rye shoots were incubated at 1-5-10-15 °C, and samples of sandy soil with rye roots were incubated at 5-10-15 °C. Concentrations of Nmin (NH4 +-N and NO3 --N) were measured after 0-1-2-4-7-10 weeks for the sandy soil and the sandy soil:rye shoot mixture, and after 0-2-7-10 weeks for the sandy soil:rye root mixture. At 1 °C, 20% of total organic N in the crop material had been mineralised after ten weeks, indicating that mineralisation at low temperatures is not negligible. Maximum mineralisation occurred at 15 °C; after ten weeks, it was 39% of total applied organic nitrogen from shoot and 35% from root material. The time course of mineralisation was calculated using an exponential decay function. It was found that the influence of temperature in the range 1-15 °C could be described by the Arrhenius equation, stating a linear increase of ln(k) with T-1, k being the relative mineralisation rate in day-1 and T the temperature (°C). A simulation model was developed in which decomposition, mineralisation and nitrification were modelled as one step processes, following first order kinetics. The relative decomposition rate was influenced by soil temperature and soil moisture content, and the mineralisation of N was calculated from the decomposition of C, the C to N ratio of the catch crop material and the C to N ratio of the microbial biomass. The model was validated first with the results of the experiment. The model was further validated with the results of an independent field experiment, with temperatures fluctuating between 3 and 20 °C. The simulated time course of mineralisation differed significantly from the experimental values, due to an underestimation of the mineralisation during the first weeks of incubation.
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  • 64
    ISSN: 1573-5036
    Keywords: carbohydrates ; carbon dioxide ; nitrogen ; nutrients ; roots ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Rising atmospheric carbon dioxide, nitrogen deposition and warmer temperatures may alter the quantity and quality of plant-derived organic matter available to soil biota, potentially altering rates of belowground herbivory and decomposition. Our objective was to simulate future growth conditions for an early successional (loblolly) and late successional (ponderosa) species of pine to determine if the physical and chemical properties of the root systems would change. Seedlings were grown for 160 days in greenhouses at the Duke University Phytotron at 35 or 70 Pa CO2 partial pressure, ambient or ambient + 5 °C temperature, and 1 or 5 mMNH4O3. Roots from harvested seedlings were analyzed for changes in surface area, specific root length, mass, total nonstructural carbohydrates (TNC), and concentrations of macro-nutrients. Surface area increased in both species under elevated CO2, due primarily to increases in root length, and this response was greatest (+138%) in loblolly pine at high temperature. Specific root length decreased in loblolly pine at elevated CO2 but increases in mass more than compensated for this, resulting in net increases in total length. TNC was unaffected and nutrient concentrations decreased only slightly at elevated CO2, possibly from anatomical changes to the root tissues. We conclude that future growth conditions will enhance soil exploration by some species of pine, but root carbohydrate levels and nutrient concentrations will not be greatly affected, leaving rates of root herbivory and decomposition unaltered.
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  • 65
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    Plant and soil 181 (1996), S. 25-30 
    ISSN: 1573-5036
    Keywords: C-mineralization ; crop residues ; incubation ; N-mineralization ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Net N-mineralization and nitrification from soil organic matter and from vegetable crop residues (leaf-blades of cauliflower and stems of red cabbage) were measured at 4 temperatures during aerobic incubation in the laboratory. C-mineralization from leaf-blades of cauliflower was monitored at 3 different temperatures. N-mineralization from soil organic matter was best described by zero order kinetics N(t)=kt whereas N- and C-mineralization from the crop residues were described by single first order kinetics. Stems of red cabbage mineralized much more slowly than leaf-blades of cauliflower. S-shaped functions were fitted to the relationship between the rate constants of both C and N-mineralization and temperature. The rate parameter κ of the S-shaped function reflects the temperature dependence of the mineralization rate k. The parameter κ for N-mineralization of the stem material (κ=5.36) was significantly higher than for the leaf-blades (κ=3.38), indicating that there is a strong interaction between temperature and resistance to degradation in the soil. N-mineralization from soil organic matter was least sensitive to temperature (κ=2.63). Temperature dependence of nitrification was not significantly different from mineralization over the temperature range considered. Rate constants for C-mineralization of cauliflower leaf-blades were higher than for N-mineralization, but the temperature dependence of the rate constants was not significantly different for both processes.
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  • 66
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    Plant and soil 190 (1997), S. 87-90 
    ISSN: 1573-5036
    Keywords: minirhizotron ; root longevity ; root mortality ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The production and mortality of roots is an important factor determining nutrient and carbon fluxes in terrestrial ecosystems. However, the effect of temperature on the longevity of roots is not understood. In this study the impact of changes in temperature on the longevity of Lolium perenne roots was determined. Plants were grown at 15 °C, 21 °C and 27 °C and their roots observed using a minirhizotron system. Major effects of temperature were measured with large reductions in root longevity occurring at higher temperatures. The implications of these data are discussed.
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  • 67
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    Plant cell, tissue and organ culture 51 (1997), S. 49-56 
    ISSN: 1573-5044
    Keywords: CO2 enrichment ; gas exchange ; in vitro environment ; light ; photoautotrophic micropropagation ; relative humidity ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Leafy or chlorophyllous explants of a number of plant species currently micropropagated have been found to have high photosynthetic ability. Their growth and development have been promoted on sugar-free medium rather than on sugar-containing medium, provided that the environmental factors, such as CO2 concentration, light intensity and relative humidity, are controlled for promoting photosynthesis and transpiration of explants/shoots/plantlets in vitro. Thus, environmental control is essential for promoting photosynthetic growth and development of in vitro plantlets. Several types of sugar-free (photoautotrophic) culture systems for large-scale micropropagation of plants have been developed. Advantages of sugar-free over conventional (heterotrophic or photomixotrophic) micropropagation systems are as follows: growth and development of plantlets in vitro are faster and more uniform, plantlets in vitro have less physiological and morphological disorders, biological contamination in vitro is less, plantlets have a higher percentage of survival during acclimatization ex vitro, and larger culture vessels could be used because of less biological contamination. Hence, production costs could be reduced and plant quality could be improved significantly with photoautotrophic micropropagation. Methods for the measurement and control of in vitro environments and the beneficial effects of environmental control on photosynthetic growth, development, and morphogenesis in large-scale production of micropropagated plantlets are presented.
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  • 68
    ISSN: 1573-5060
    Keywords: breeding ; genotype x environment interaction ; palmitic ; stearic ; temperature ; Glycine max ; soybean
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Concern over high saturates in human diets has prompted the development of soybean [Glycine max (L.) Merr.] lines producing oil with reduced saturated fatty acid concentration. To better understand those factors that influence phenotypic expression for palmitic and stearic acid content in soybean, thirty soybean lines random for saturated fatty acid content were grown in eight field environments contrasting for mean temperature during seed-filling. Palmitic and stearic acid content varied significantly (P〈0.01) both among genotypes and across environments, while genotype x environment interactions were reflected in changes in line variance and ranking for both traits. Therefore selection of a superior genotype for saturated fatty acid composition may not correlate well from one environment to another. In general, early-maturing lines were less sensitive than later-maturing lines in their response to changes in mean daily temperature for palmitic concentration. However, factors in addition to temperature appeared to influence genotype response for stearic acid content. It appears that genetic systems conditioning palmitic and stearic acids are independent, and that separate breeding strategies need be adopted to make simultaneous improvement for these two oil traits. In summary, development of soybean lines with low or high saturated fatty acid content may be accomplished through evaluation and selection in a few environments contrasting for temperature.
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  • 69
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    Plant growth regulation 20 (1996), S. 225-236 
    ISSN: 1573-5087
    Keywords: abscisic acid ; Carthamus tinctorius ; safflower ; salinity ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Growth and contents of sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), chloride (Cl), phosphorus (P) and sulphur (S) in shoot and root tissues of Carthamus tinctorius plants were measured at combinations of four nutrient solution osmotic potentials (Ψs=0, -0.3, -0.6 and -0.9 MPa) induced by NaCl and CaCl treatments, three constant temperatures (T) ranging from 15 to 35°C and four abscisic acid (ABA) concentrations (0,10,50 and 100 mg L−1). Unstressed and stressed plants grown in optimal temperature conditions (25°C) maintained higher growth rates (dry mass production) than plants grown under low and high temperatures (15 and 35°C respectively). Shoot and root growth (dry mass production) were largely inhibited by salinity but the magnitude of growth inhibition was temperature dependent. Safflower plants respond to salinity stress by increases in Ca, Cl and to a lesser extent Na in their shoots and roots and by a decrease in the ratio of fresh to dry weight. The ratio of K/Na was decreased progressively on salinization. With stressed plants, ABA application reduced the toxicity of salt treatment, improved K uptake under salinity, effectively increased K/Na ratio and helped the plants to avoid Na toxicity and sometimes enhanced growth. The effect of ABA on the growth was more pronounced at optimum temperature (25°C). The association between the internal mineral element concentrations was largely affected by ABA application and temperature change but a wide fluctuation in response was noticed. The effects of single factors (Ψs, T and ABA) on the growth and mineral contents were statistically significant. Also, bifactorial (Ψs× T, Ψs × ABA and T × ABA) and three factorial (Ψs × T × ABA) interactions significantly affected the parameters. Further statistical treatment of the data (coefficient of determination η2) led to four important findings: (1) Salinity (Ψs) was dominant in affecting Ca and Cl contents in both shoot and root as well as root Na content. (2) Temperature (T) had a dominant effect on growth, shoot K, Mg, P, S and root P, and S contents (3) The share of Ψs × T × ABA interaction was dominant for root Na and Mg contents. (4) The single factors and their interactions had a dual role in their subsidiary effects.
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  • 70
    ISSN: 1573-5087
    Keywords: gibberellin ; leaf elongation ; light intensity ; Rht alleles ; temperature ; Triticum aestivum L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Near-isogenic wheat lines differing in height-reducing (Rht) alleles, in each of two cultivars, were used to investigate the effects of light intensity and of their interaction with temperature and GA3 application, on the elongation of the coleoptile and the first seedling leaf. Darkness caused a conspicuous increase in the lengths of the coleoptile and of the sheath and lamina of the first leaf, in GA3 treated and untreated seedlings of all genotypes grown at 11 and 25°C. The genotype effects and the effects of light intensity and GA3 application on leaf length were ascribed entirely to their effects on the rate of leaf elongation since the duration of leaf elongation was not affected by these factors. Temperature elevation from 11 to 25°C caused a 55% shortening of the duration of leaf elongation and a concomitant increase in elongation rate, which diminished with increased genotypic dwarfness. Accordingly, temperature elevation resulted in a significant reduction in leaf-length of the light-grown dwarf genotypes and the dark-grown dwarf and semi-dwarf genotypes. It is suggested that this temperature × light × genotype interaction effect is due to environmental dependent upper limits of elongation rate set by the Rht alleles.
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    Fish physiology and biochemistry 16 (1997), S. 381-393 
    ISSN: 1573-5168
    Keywords: pike ; eggs ; larvae ; embryonic development ; fatty acid ; lipid class ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To establish the changes which occur during embryogenesis and early larval development, eggs, yolk sac larvae and swim-up larvae of pike were examined for lipid class and fatty acid composition. At a water temperature of 15.5°C, the embryonic phase was short (6 days) and characterized by a 41.3% decline in the lipid content of eggs, accompanied by large reductions in the amount of phosphatidylcholine (41.4% decrease), sterol esters and triacylglycerols (respectively a 41.2% decrease and a 58.1% decrease), but not phosphatidylethanolamine which increased markedly (35.6%). By the time of yolk sac absorption (7 to 11 days after fertilization) the larvae remained inactive and a limited utilization of lipids was observed. Yolk sac phosphatidylcholine was selectively incorporated into larval bodies while the levels of other lipid classes remained unchanged in the yolk. When the swim bladder was filled and the swimming stage was reached (11 days to 13 days af), the yolk was completely depleted and yolk phosphatidylcholine together with yolk triacylglycerols were catabolised. Yolk phosphatidylethanolamine and yolk sterol esters were partly incorporated into the body lipids. In the subsequent swim-up larval stage (13 to 15 days af), a steady decrease in lipids was observed (41.6%). Fluctuations in the levels of polyunsaturated fatty acids, monounsaturated fatty acids or saturated fatty acids examined from eggs or larvae were consistent with changes in lipid classes during pike development. During yolk sac absorption, pike incorporated yolk PUFA released on hydrolysis of phosphatidylcholine into the larval body. The results are discussed with reference to water temperature and in relation to the ontogenic and ecological context of pike development.
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    Fish physiology and biochemistry 16 (1997), S. 355-364 
    ISSN: 1573-5168
    Keywords: Na-K-ATPase ; pNPPase ; channel arrest ; fish heart ; thermal acclimation ; anoxia ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of seasonal acclimatization, thermal acclimation and anoxic exposure on total cation-activated ATPase and sarcolemmal Na-K-ATPase activities of crucian carp heart were measured. The total cation-activated ATPase showed a positive correlation with environmental temperature: activity was highest in mid summer and lower in early spring and late autumn. The decline of total ATPase activity during cold seasons suggests that energy consumption of the heart is reduced during the anoxic winter period by depression of ATP utilization rate. In contrast to the total ATPase activity, the activity of sarcolemmal Na-K-ATPase did not correlate strongly with environmental temperature but remained relatively constan during most of the study period. However, in late autumn when oxygen content of water is low, a prominent decline in Na-K-ATPase activity was noted. The latter finding suggests that the activity of Na-K-pump of the cardiac sarcolemma is unaffected by seasonal temperature changes but is depressed by hypoxic exposure. In accordance with this short-term anoxia (100 h) in laboratory conditions reduced Na-K-ATPase or pNPPase activities of cardiac homogenates while long-term thermal acclimation (〉4 weeks) was ineffective in this respect. The present findings suggest that cation-activated ATPases of crucian carp heart are downregulated during winter, and part of this reduction is due to anoxic depression of sarcolemmal Na-K-ATPase.
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  • 73
    ISSN: 1573-515X
    Keywords: acidification ; aluminium ; Arrhenius’ law ; calcium ; cation leaching ; climate ; ion equilibrium ; forest soil ; N-cycle ; N-deposition ; nitrification ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Increased emissions of nitrogen compounds have led to atmosphericdeposition to forest soils exceeding critical loads of N overlarge parts of Europe. To determine whether the chemistry offorest soils responds to changes in throughfall chemistry, intactsoil columns were reciprocally transplanted between sites, withdifferent physical conditions, across a gradient of N and Sdeposition in Europe. The transfer of a single soil to the various sites affected itsnet nitrification. This was not simply due to the nitrificationof different levels of N deposition but was explained bydifferences in physical climates which influenced mineralizationrates. Variation in the amount of net nitrification between soiltypes at a specific site were explained largely by soil pH. Within a site all soil types showed similar trends in netnitrification over time. Seasonal changes in net nitrificationcorresponds to oscillations in temperature but variable time lagshad to be introduced to explain the relationships. WithArrhenius‘ law it was possible to approximate gross nitrificationas a function of temperature. Gross nitrification equalled netnitrification after adaptation of the microbial community oftransplanted soils to the new conditions. Time lags, andunderestimates of gross nitrification in autumn, were assumed tobe the result of increased NH 4 + availability due either tochanges in the relative rates of gross and net N transformationsor to altered soil fauna-microbial interactions combined withimproved moisture conditions. Losses of NO 3 - were associated with Ca2+and Mg2+ in non-acidified soil types and with losses ofAl3+ in the acidified soils. For single soils the ionequilibrium equation of Gaines-Thomas provided a useful approximationof Al3+ concentrations in the soil solution as a functionof the concentration of Ca2+. The between site deviationsfrom this predicted equilibrium, which existed for single soils, couldbe explained by differences in throughfall chemistry which affectedthe total ionic strength of the soil solution. The approach of reciprocally transferring soil columnshighlighted the importance of throughfall chemistry, interactingwith the effect of changes in physical climate on forest soilacidification through internal proton production, in determiningsoil solution chemistry. A framework outlining the etiology offorest die-back induced by nitrogen saturation is proposed.
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    Fish physiology and biochemistry 16 (1997), S. 139-155 
    ISSN: 1573-5168
    Keywords: season ; metabolic organization ; muscle ; fish ; temperature ; lipid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This study examined how muscle metabolic organization varied during an annual cycle in which rainbow trout (Oncorhynchus mykiss) were held in outdoor holding ponds in which they were exposed to natural changes in temperature (range 0.2 to 15.6°C) and photoperiod. We examined the activities of glycolytic and mitochondrial enzymes in red and white muscle to evaluate whether trout enhance their capacity for lipid and carbohydrate oxidation during cold-acclimization. When assayed at habitat temperature, the enzyme activities generally increased in spring to reach a maximum in summer followed by a decrease in the fall. This led to significantly higher activities at warm than cold periods for all enzymes measured in red muscle and all but one in white muscle. The activities at 10°C provided little evidence for compensatory adjustments of aerobic capacity. Particularly in red muscle, enzyme levels at 10°C were generally lower during cold than warm periods. The variation of enzyme activities throughout the cycle was not due to changes in protein concentration, as the same responses were observed when activities were expressed per g wet mass or per mg protein. Although the aerobic capacity did not increase with cold-acclimatization, the relative capacity for lipid oxidation was higher in winter than in summer trout. In contrast, the relative capacity for aerobic glycolysis was higher in summer than in winter trout. Thus, the metabolic capacities of trout muscle undergo seasonal reorganization.
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    Fish physiology and biochemistry 17 (1997), S. 231-236 
    ISSN: 1573-5168
    Keywords: growth ; salmon ; smoltification ; insulin ; insulin-like growth factor I (IGF-I) ; growth hormone ; thyroxine ; photoperiod ; temperature ; nutrition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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    Plant cell, tissue and organ culture 48 (1997), S. 195-201 
    ISSN: 1573-5044
    Keywords: cytokinins ; in vitro ; Lonicera caerulea ; minerals ; plant tissue culture ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Factors affecting axillary shoot development of blue honeysuckle in vitro were studied with two genotypes, Lonicera caerulea f. caerulea and L. caerulea f. edulis. There was a linear relationship between the concentration of N6-benzyladenine (1.1 to 17.8 μmol l−1) and the number of axillary branches produced (3 to 13 new shoots), biomass production and callus formation of the form caerulea shoot explants. The formation of second-order branches responded most strongly to the cytokinin treatments. Axillary branching was significantly lower at 24/20 °C (mean day maximum/night minimum) than at 26/20 °C. When the cultures were incubated at 28/21 °C, the number of axillary shoots produced was highest, 10.4 and 21.1 in the forms caerulea and edulis, respectively, but apical injuries were more frequent (17 in the form caerulea, 49 in the form edulis) and shoot morphology changed as compared to the shoots developed at lower temperatures. In the form edulis, the production of axillary shoots also increased by diluting the mineral nutrients of the MS medium to 75. Further dilution of minerals to 50 increased the incidence of apical shoot necrosis. It was shown that the stimulation of axillary branching by increased temperature or decreased nutrient supply was not caused by reduced apical dominance related to shoot tip injuries.
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    Journal of clinical monitoring and computing 12 (1996), S. 243-249 
    ISSN: 1573-2614
    Keywords: Cardiac catheter ; cardiac function ; clinical pathology ; hemodynamics ; histopathology ; temperature ; thermodilution cardiac output
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Medicine
    Notes: Abstract The safety of a new continuous cardiac output monitoring system, recently introduced by Baxter Healthcare Corporation's Edwards Critical-Care Division, was evaluated in normal sheep. The study compared the biocompatibility and safety of the Vigilance® CCO Monitoring System, which employs a continuous cardiac output (CCO) catheter with Baxter Edwards' standard Paceport™ pulmonary artery catheter. The CCO catheter, which monitors hemodynamic pressures and provides continuons measurement of cardiac output based on the thermodilution principle, contains a thermal filament that is powered and controlled by a unique cardiac output monitor. Parameters were measured periodically in conscious animals and complete necropsies were performed alter each study. Time Control, Paceport™, and four CCO groups were studied. Selected groups were studied for 3 days (acute), 7 days (subacute), and/or 4 weeks after 3 days of continuons use (recovery). Results showed no significant differences between the CCO and Paceport™ catheters in any of the parameters studied. On gross pathology, observations were similar. The only difference between catheters were microscopie findings of focal subendothelial or subendocardial changes correlated with areas that could have corne into contact with the CCO catheter. In acute groups, these changes consisted of a localized myofiber degeneration or necrosis, while in subacute and recovery groups, consisted only of fibrosis. None of the changes were clinically significant. Thus, the CCO catheter, used in conjunction with the Vigilance® CCO Monitoring System, appears to pose no additional risk over a standard Paceport™ catheter in normal sheep after continuons use for up to 7 days.
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    Colloid & polymer science 105 (1997), S. 322-325 
    ISSN: 1435-1536
    Keywords: Rheology ; surfactant solutions ; micelles ; phase transition ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Aqueous solutions of cationic surfactant with binding counterions exhibit a transition under shear. In this paper the steady shear properties of semidilute aqueous micellar solutions (cetylpyridinium chloride and sodium salicylate in brine) are presented as a function of concentration and temperature. The shear thinning behavior of this system could be described by the Carreau model at low shear rate and by a power law at higher shear rate. The temperature dependence of the zero shear viscosity follows an Arrhenius relationship. The critical shear rate at which the viscosity departs from its zero shear value is found to increase with temperature indicating the influence of this parameter on transition.
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  • 79
    ISSN: 1572-9702
    Keywords: Ixodes pacificus ; life history ; ecology ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The timing of oviposition and hatching of Ixodes pacificus was investigated in the field and at constant temperatures in the laboratory. Replete females held at temperatures between 9 and 29°C began depositing eggs a mean of 9–70 days after drop off. Egg masses held between 12 and 25°C commenced hatching 25–178 days after the onset of oviposition. Eggs held at 9 or 29°C did not hatch. The lower temperature thresholds for development (LTD) for oviposition and hatching were 6.5 and 9°C, respectively. The number of degree days required for oviposition and hatching was 173 and 588, respectively. Replete females placed in the field on 2 December through to 8 March deposited eggs from 2 February through to 24 April; the eggs commenced hatching between 2 July and 21 August. Unfed larvae from two of 20 egg masses survived through the winter and fed readily when exposed to deer mice (Peromyscus maniculatus) on 22 April. Replete larvae were returned to the field and moulted between 9 and 21 August. Larvae exposed to deer mice in August, 4 weeks after hatching, also fed readily. Although further studies are needed to clarify the timing of nymphal development, the present study suggests that I. pacificus requires more than 1 year to complete its life cycle.
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    Experimental and applied acarology 21 (1997), S. 247-256 
    ISSN: 1572-9702
    Keywords: Diel abundance ; activity ; temperature ; Ixodes ricinus ; ticks
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The diel ‘activity’, i.e. availability, of Ixodes ricinus larvae, nymphs and adults was investigated in a meadow and a forest habitat near Stockholm during 1991–1993. Generally, the immature ticks were more prevalent in the forest than in the meadow. In the meadow, the mean larval and adult numbers varied significantly between 4 h time intervals with the peak activity from 2300 to 0300 h. In the forest, the tick numbers did not differ significantly between the time intervals. The association of the tick activity with certain meteorological variables was strongest in the meadow, where the mean numbers of all tick stages were negatively correlated with the temperature. The relative humidity was positively correlated only with the mean numbers of larvae. In contrast, the larval activity in the forest was positively and negatively correlated with the temperature and relative humidity, respectively, while the nymphal and adult activity showed no association with these climatic variables. The impact of the host activity on the tick diel activity is also discussed.
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    International journal of thermophysics 17 (1996), S. 551-560 
    ISSN: 1572-9567
    Keywords: density ; HCFC 141b ; pressure ; temperature ; Tait equation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The density of HCFC 141b has been measured at several temperatures between 260 and 320 K, Mid pressures up to 20 MPa, with a mechanical oscillator densimeter. The densimeter was calibrated with 2,2,4-trimethylpentane, whose density was obtained from a correlating cyuation with 0.3% uncertainty. The density data obtained for HCFC 14H) hits a reproducibility of 0.05% and an uncertainty of 0.3%. The data obtained were fitted to a Tait-type equation. which reproduced the experimental densities within 0.11 % and were compared with the data obtained in other works.
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  • 82
    ISSN: 1573-5087
    Keywords: ACC ; Amaranthus retroflexus ; dormancy ; ethephon ; ethylene ; germination ; gibberellic acid ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Dormant Amaranthus retroflexus seeds do not germinate in the dark at temperatures below 35°C. Fully dormant seeds germinate only at 35–40°C whereas non-dormant ones germinate within a wider range of temperatures (15 to 40°C). Germination of non-dormant seeds requires at least 10% oxygen, but the sensitivity of seeds to oxygen deprivation increases with increasing depth of dormancy. 10−6 to 10−4 M ethephon, 10−3 M 1-aminocyclopropane 1-carboxylic acid (ACC) and 10−3 M gibberellic acid (GA3) break this dormancy. In the presence of 10−3 M GA3 dormant seeds are able to germinate in the same range of temperatures as non-dormant seeds. The stimulatory effect of GA3 is less dependent on temperature than that of ethephon, while ACC stimulates germination only at relatively high temperatures (25–30°C). The results obtained are discussed in relation to the possible involvement of endogenous ethylene in the regulation of germination of A. retroflexus seeds.
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    Plant growth regulation 18 (1996), S. 175-181 
    ISSN: 1573-5087
    Keywords: Germination ; gibberellin A4/7 ; light ; parsley ; Petroselinium crispum ; seeds ; temperature ; umbel position
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The percentage germination of seeds of parsley cv. Imperial Curled was higher in the light than in the dark, the high temperature limits for germination being 30 and 28°C for light and dark respectively. At the higher temperatures, the germination rate was slower in the dark. At 30°C, treatment with a gibberellin A4/7 mixture at 2 × 10−4 M partially alleviated the inhibiting effect of darkness on the germination percentage. Pre-incubation of parsley seeds at 35°C in the dark for 30 h increased the rate, but decreased the percentage, of germination of seeds incubated at 15°C in the light. Germination and seedling emergence studies were made on seed harvested from four different umbel positions. Although heavier seeds were produced from primary umbels than from other umbel orders, they were less viable as measured by seedling emergence in the glasshouse. The rate of emergence was decreased with increasing umbel order i.e. with later seed development: this was reflected in subsequent seedling weights, with seedlings from quarternary umbel seeds being about half the weight of those from primary umbel seeds. The upper temperature limit for dark germination was only slightly affected by umbel order, with quarternary umbel seeds being the most thermo-inhibited.
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  • 84
    ISSN: 1573-5060
    Keywords: adaptation ; common bean ; flowering ; photoperiod ; temperature ; Phaseolus vulgaris
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Photoperiod response of flowering in common bean (Phaseolus vulgaris L.) is thought to be controlled by the genes Ppd and Hr. However, cultivars also vary in the degree that cooler temperatures reduces their sensitivity to photoperiod. To examine the inheritance of this temperature sensitivity, crosses of cvs. Gordo x de Celaya and Flor de Mayo × Rojo 70 were evaluated at two sites differing in mean temperature and using 12.5-h natural photoperiod or 18-h artificially extended photoperiod. Under 18-h photoperiod at the warmer site, Palmira, no plants of the parents or of the F2 populations flowered, confirming that the parents were sensitive to photoperiod. Under 12.5-h photoperiod at the cooler site, Popayan, the parents for each cross flowered at similar dates and no segregation for days to flower was observed. However, under 18-h photoperiod, de Celaya and Rojo 70 and the F1 populations did not flower within 100 days after planting, while the F2 and F3 populations showed segregation that was consistent with single gene inheritance, late flowering being dominant. Late flowering at Popayan under 18-h photoperiod indicates a lack of temperature sensitivity, so temperature insensitivity of the photoperiod response was dominant to sensitivity. The name Tip, for “temperature insensitivity of photoperiod response”, is proposed for this gene, with the recessive form of this gene conditioning earlier flowering at cooler temperatures with long daylengths. It is recognized that the observed segregation patterns could represent the effect of multiple alleles at the Ppd or Hr loci, and studies are proposed to test this possibility with molecular markers and recombinant inbred lines.
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  • 85
    ISSN: 1573-5060
    Keywords: cowpea ; flowering ; photoperiod ; stability analysis ; temperature ; Vigna unguiculata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Twenty-one genotypes of cowpea (Vigna unguiculata), comprising landraces and varieties, were grown in 22 photothermal environments in Nigeria and Niger, West Africa, and a stability analysis of days from sowing to flowering (f) was carried out. Cowpeas are rarely insensitive to photoperiod; they are typically quantitative shortday plants wherein f is delayed when photoperiod (P) is longer than the critical photoperiod (P c ). Therefore, in order to quantify genotypic variation in temperature sensitivity, genotype f was regressed against the mean trial f in circumstances where P〈P c (i.e. approximately ≤ 13 hd-1) and mean temperature (T) was between 19° and 28° C. Correspondingly, in order to assess genotypic variation in photoperiod sensitivity, trials where T was near optimal (25°–28° C) but where P ranged from 10–14.5 hd-1 were used. These stability analyses detected no significant differences (P〉0.05) between genotypes 9n temperature sensitivity but revealed significant differences (P〈0.001) in photoperiod sensitivity. Regression coefficients from the stability analysis were strongly correlated (r=0.94, 19df) with a photoperiod sensitivity constant, c′, determined from a photothermal flowering model. A stability analysis of f from field trials can therefore identify and quantify genotypic variation in response to temperature and photoperiod in cowpea.
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  • 86
    ISSN: 1573-5060
    Keywords: adaptation ; flowering ; photoperiod ; temperature ; germplasm ; characterisation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Descriptor lists for the major cereals and grain legumes include information on the duration from sowing to flowering. This is because the first step towards maximizing crop yield by agronomic management or plant breeding is to ensure that the phenology of the crop is well matched to the resources and constraints of the production environment. In this context, durations from sowing to flowering are of critical importance if crops sown on the appropriate date and at the appropriate density are to have the potential to yield well in a given environment. In most annual crops, the timing of phenological events is modulated primarily by responsiveness to photoperiod and temperature with large differences in sensitivity among genotypes. Irrespective of the crop, many advantages accrue from analyses of these photothermal responses not in terms of the evaluation descriptor ‘time from sowing to flowering (f)’ but in terms of the ‘rate of progress towards flowering (1/f)’. A computer program RoDMoD has been developed to convert evaluation descriptors for times of flowering to characterisation descriptors of the flowering response of a genotype to photoperiod and temperature. The program and the associated phenological model were developed from research undertaken in controlled environments and then validated in the field over wide ranges of locations and seasons. These advances should contribute to the development of cultivars phenologically well adapted to their target environments.
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  • 87
    ISSN: 1573-5060
    Keywords: Persea americana ; avocado humidity ; Greece ; pollen grain germination ; temperature ; fruit-set
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Optimum in vitro germination of pollen grain of the avocado cultivars Fuerte, Nabal, Ettinger, Bacon and Zutano occurred at 25 °C. However, there were significant differences between cultivars in percentage germination and relative humidity (RH) requirements for optimum pollen grain growth. The most sensitive cultivar to relative humidity was Fuerte, in which the germination of pollen grain rose from 11.4%, at 40% RH, to about 50%, after one hour at 100% RH. The germination% of Nabal pollen grain was already high at 40% RH and was not increased by higher relative humidity. Increased relative humidity also helped to sustain the viability of avocado pollen. At 30 °C and 5% RH the pollen grains of Fuerte quickly lost its ability to germinate, at 40% RH for 1 hour, germination was reduced spectacularly compared to pollen kept in saturated with moisture environment where it was not affected the first 24 hours. The effects of temperature and relative humidity on fruit-set and yield of avocado are discussed.
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  • 88
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    Biogeochemistry 35 (1996), S. 433-445 
    ISSN: 1573-515X
    Keywords: ammonium oxidation ; growth rate ; maintenance energy ; modeling ; nitrification ; soil nitrate ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract To model nitrification rates in soils, it is necessary to have equations that accurately describe the effect of environmental variables on nitrification rates. A variety of equations have been used previously to describe the effect of temperature on rates of microbial processes. It is not clear which of these best describes the influence of temperature on nitrification rates in soil. I compared five equations for describing the effects of temperature on nitrification in two soils with very different temperature optima from a California oak woodland-annual grassland. The most appropriate equation depended on the range of temperatures being evaluated. A generalized Poisson density function best described temperature effects on nitrification rates in both soils over the range of 5 to 50 °C; however, the Arrhenius equation best described temperature effects over the narrower range of soil temperatures that normally occurs in the ecosystem (5 to 28 °C). Temperature optima for nitrification in most of the soils were greater than even the highest soil temperatures recorded at the sites. A model accounting for increased maintenance energy requirements at higher temperatures demonstrates how net energy production, rather than the gross energy production from nitrification, is maximized during adaptation by nitrifier populations to soil temperatures.
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  • 89
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    Fish physiology and biochemistry 17 (1997), S. 9-24 
    ISSN: 1573-5168
    Keywords: growth hormone ; insulin-like growth factor I ; salmonids ; secretion ; regulation ; metabolism ; photoperiod ; temperature ; smoltification ; seawater tolerance ; appetite ; aggression ; predator avoidance ; behaviour
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The elucidation of the molecular structure of salmon growth hormone (GH) in the mid-1980's paved the way for a new era of endocrinological research. Establishment of homologous immuno- and receptor-assays have made studies of the secretion, tissue and plasma GH levels, GH turn-over and GH receptor concentrations possible. This overview attempts to summarize the present understanding of the biological roles of GH in salmon. Although the involvement of GH in the regulation of physiological processes throughout the salmon life history has yet to be comprehensively explored, the hormone has already been demonstrated to have several important functions. GH is a principal regulator of somatic growth in salmonids. The growth-stimulating effect of GH is probably integrated with that of insulin-like growth factor I (IGF-I), as in later vertebrates. GH stimulates protein synthesis and improves feed conversion during growth. The hormone also promotes lipid and glycogen breakdown as well as gluconeogenesis, functions which are probably of great importance during starvation when GH levels are seen to increase. During parr-smolt transformation of anadromous salmonids, circulating GH levels appear to be governed by environmental cues. Increasing springtime daylength elevates GH levels, and temperature modulates the photoperiod regulation of GH. The seawater-adapting role of GH during the parr-smolt transformation is complex. In freshwater, GH improves hypoosmoregulatory ability by stimulating branchial Na+,K+-ATPase activity and probably also acts in kidney and intestine. Following seawater entry, GH levels and turn-over increase transiently, probably to further increase seawater tolerance. Accumulating in vitro and in vivo data support the conclusion that GH is involved in the regulation of sexual maturation in salmonids although further studies are needed to establish the exact role of GH in this process. GH increases appetite but it is unclear whether the hormone effects the central nervous system directly, or acts indirectly through metabolic changes. GH increases swimming activity as well as dominant feeding behaviour and diminishes anti-predator behaviour of juvenile salmonids. The GH-induced changes of behavioural patterns imply that there exists an ecological trade-off between high growth rate and long-term survival which may explain why natural fish populations normally grow at sub-maximal rates. Current knowledge indicates that GH is an important and multi-functional hormone in salmon and a central mediator of seasonal changes in physiology and behaviour. The regulatory effects of GH are also of great applied interest as they are likely to affect both product quality in aquaculture and long-term survival of released fish.
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  • 90
    ISSN: 1573-5168
    Keywords: temperature ; acclimation ; cytokine ; enhancer ; goldfish ; hemopexin ; hepatopancreas ; immune system ; plasma protein ; lipopolysaccharide ; transcription ; Wap65
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The expression of the Wap65 mRNA was compared between hepatopancreas, intestine, ovary, heart, gill, eye, skin, hemocytes, muscle, and brain from 30 °C-acclimated goldfish (Carassius auratus) by reverse transcription PCR, demonstrating the highest levels of expression of the gene in the hepatopancreas. Other tissues expressing the gene were ovary, gill, eye, and muscle, whereas Wap65 mRNA could not be detected in intestine, heart, skin, and brain. In Northern blot analysis, levels of Wap65 mRNA in the hepatopancreas increased after raising water temperature from 10 to 30 °C. The transcript levels reached a maximum of 40-fold on day 3 following temperature shift. On day 21 after raising water temperature, levels were 10-fold compared with those of the 10 °C-acclimated fish. Subsequently, in order to elucidate the transcriptional mechanisms of Wap65, a part of the Wap65 gene was cloned from a genomic library. The 5′-flanking region and introns of this gene contained enhancer motifs including cytokine responsive elements previously identified in mammals. The suggesting that some of these motifs are involved in the transcriptional regulation of Wap65, was tested by administering of lipopolysaccharide (LPS) to the 10 °C-acclimated goldfish. This resulted in the accumulation of Wap65 mRNA in the hepatopancreas, suggesting the involvement of immune associated factors in the regulation of transcription of Wap65.
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  • 91
    ISSN: 1573-5168
    Keywords: teleost ; sea bass ; Dicentrarchus labrax ; photoperiod ; temperature ; reproduction ; spawning ; gametogenesis ; estradiol ; vitellogenin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The annual profile of plasma vitellogenin (VTG) and 17ß-estradiol (E2) levels, as well as gonadal development and spawning characteristics were investigated in captive female sea bass (Dicentrarchus labrax). Endocrine and gonadal changes were studied in fish reared under natural conditions or exposed to manipulated photothermal cycles. In natural conditions of photoperiod and temperature, sea bass spawned from February through March (East coast of Spain, 40°N 0°E). One or two months of constant long-days (15L/9D) in a constant short-day photoperiod regime (9L/15D) all-year-round, given early in the year (March and March–April), advanced spawning by 3 months. The same treatment applied later in the year (September–October) delayed spawning by 1 month, compared to controls. In all groups, changes in plasma VTG levels were correlated with E2 levels, oocyte growth and spawning time. In control females, VTG was low (〈100 ng ml-1) during the summer, until its first surge in plasma 4 months before the beginning of spawning. The VTG (3.1 ± 0.3 mg ml-1) and E2 (4.1 ± 0.5 ng ml-1) levels showed a single annual peak during late vitellogenesis, the time of the highest proportion of vitellogenic oocytes in the ovary. Constant high levels of VTG (1–1.4 mg ml-1) and E2 (1.6–1.9ng ml-1) were maintained during the entire spawning time, together with the presence of vitellogenic oocytes, suggesting the existence of several waves of oocyte growth in the ovary and thus, several spawns per female. Endocrine profiles and oocyte development in fish exposed to constant photoperiods were similar to controls, but were shifted in time in relation to the displacement of the spawning time. In the fish showing advanced spawns, the duration of the gametogenic proces was compressed when compared to controls. The differences observed in the evolution of the reproductive-related factors in the advanced groups, which were exposed to a reduction in temperature to 15°C, suggest an influence of the temperature in the early stages of the reproductive cycle in sea bass.
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  • 92
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    Water, air & soil pollution 99 (1997), S. 201-208 
    ISSN: 1573-2932
    Keywords: freshwater sediments ; radiocaesium ; fixation ; ionic composition ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The objective of this study was to verify in which way the ionic composition of the sediment and that of the overlying water column may have an effect on radiocaesium fixation, through possible structural modifications of the frayed edge sites (FES) pools of the sediments. Two experimental protocols have been considered: i) a condition in which sediments were homoionically saturated with either potassium, ammonium, calcium, magnesium or sodium ions, and ii) a mixed potassium-calcium scenario in the liquid phase. Nine freshwater sediments from four different locations were used in this study. For homoionic potassium and ammonium saturated sediments a nearly quantitative radiocaesium desorption (90-100%) was observed, whereas for calcium and magnesium the desorption yields were about 20%. It appears that the action of strongly hydrated ions (Na+, Mg2+, Ca2+) leads to a pronounced enhancement of radiocaesium fixation in the solid phase, whereas poorly hydrated ions (K+, NH4 +) have the opposite effect and promote sorption reversibility. Another issue considered in this study concerns the effect of temperature and sediment drying on the radiocaesium fixation. Drying the sediments at 110°C leads to a significant increase in radiocaesium fixation levels, while drying the sediments at room temperature (25°C) has a very limited effect on radiocaesium fixation and appears to put a brake on the aging effects.
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  • 93
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    Water, air & soil pollution 99 (1997), S. 201-208 
    ISSN: 1573-2932
    Keywords: freshwater sediments ; radiocaesium ; fixation ; ionic composition ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The objective of this study was to verify in which way the ionic composition of the sediment and that of the overlying water column may have an effect on radiocaesium fixation, through possible structural modifications of the frayed edge sites (FES) pools of the sediments. Two experimental protocols have been considered: i) a condition in which sediments were homoionically saturated with either potassium, ammonium, calcium, magnesium or sodium ions. and ii) a mixed potassium-calcium scenario in the liquid phase. Nine freshwater sediments from four different locations were used in this study. For homoionic potassium and ammonium saturated sediments a nearly quantitative radiocaesium desorption (90–100%) was observed, whereas for calcium and magnesium the desorption yields scene about 20%. It appears that the action of strongly hydrated ions (Na+, Mg2+, Ca2+) leads to a pronounced enhancement of radiocaesium fixation in the solid phase, whereas poorly hydrated ions (K+, NH4 +) have the opposite effect and promote sorption reversibility. Another issue considered in this study concerns the effect of temperature and sediment drying on the radiocaesium fixation. Drying die sediments at 110°C leads to a significant increase in radiocaesium fixation levels, while drying the sediments at room temperature (25°C) has a very limited effect on radiocaesium fixation and appears to put a brake on the aging effects.
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  • 94
    ISSN: 1573-5168
    Keywords: temperature ; malate dehydrogenase ; acclimation ; adaptation ; grass carp ; Ctenopharyngodon idella ; teleost fish ; thermostability ; isozyme ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Malate dehydrogenase isozymes of grass carp,Ctenopharyngodon idella, were identified by mitochondrial preparation and thermal denaturation. The structural and kinetic characteristics of chromatographically separated thermostable and thermolabile cMDHs were different in (1) half-life at 42°C, 10 min and 24 h, respectively, (2) optimal substrate, oxaloacetate and malate, concentrations, and (3) the apparent Michaelis-Menten constants of NADH and oxaloacetate. Total MDH activity in white muscle of 11°C-acclimated fish was about twice that of the 30°C-acclimated group. In addition, the ratio of the thermostable to thermolabile cMDH activity in white muscle of 30°C-acclimated fish was significantly higher than that of 11°C-acclimated fish. These results suggest that temperature acclimation can induce temperature compensation in MDH activity and differential expression of thermostable and thermolabile cMDH isozymes in freshwater fish.
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  • 95
    ISSN: 1573-0778
    Keywords: fluidized-bed reactor ; monoclonal antibody ; on-line monitoring ; sample system ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The monoclonal-antibody production of an immobilized hybridoma cell line cultivated in a fluidized-bed reactor was monitored on-line for nearly 900 h. The monoclonal antibody concentration was determined by an immuno affinity-chromatography method (ABICAP). Antibodies directed against the product, e.g. IgG, were immobilized on a micro-porous gel and packed in small columns. After all IgG present in the sample was bound to the immobilized antibodies, unbound proteins were removed by rinsing the column. Elution of the bound antibodies followed and the antibodies were determined by fluorescence. The analytical procedure was automated with a robotic device to enable on-line measurements. The correlation between the on-line determined data and antibody concentrations measured by HPLC was linear. A sampling system was constructed, which was based on a pneumatically actuated in-line membrane valve integrated into the circulation loop of the reactor. Separation of the cells from the sample stream was achieved by a depth filter made of glass-fibre, situated outside the reactor. Rapid obstruction of the filter by cells or cell debris and contamination of the sample system was avoided by intermittent rinsing of the sample system with a chemical solution. The intermittent rinsing of the filter, which had a surface of 4.8 cm2, resulted in an operational capacity of up to 40 samples (1.0 l total sample volume). Both the sampling system and the analytical device functioned without failure during this long-term culture. The culture temperature was varied between 34 and 40 °C. Raising the temperature from 34 up to 37 °C resulted in a simultaneous increase of growth and specific antibody production rate. Specific metabolic rates of glucose, lactate, glutamine and ammonium stayed constant in this temperature range. A further enhancement of temperature up to 40 °C had a negative effect on the growth rate, whereas the specific monoclonal antibody production rate showed a small increase. The other specific metabolic rates also increased in the temperature range between 38 to 40 °C.
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  • 96
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    Photosynthetica 33 (1997), S. 125-138 
    ISSN: 1573-9058
    Keywords: Actinidia deliciosa ; CO2 concentration ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The lack of an indicator of the state of bud development during the dormant period has been a major difficulty in studying the effects of winter chilling on subsequent shoot growth and flowering. We considered that respiration rate (RD) might provide such an index, so developed a technique for the non-destructive measurement of the RD of individual dormant buds of kiwifruit (Actinidia deliciosa). A closed configuration gas exchange system was used. The low RD of dormant buds required the use of an unusually small system volume. As a consequence, it was necessary to modify the conventional closed system so that most of the system volume could be sampled for analysis. Increases in CO2 concentration during a measurement were determined by injecting gas samples into a stream of air flowing through an infrared gas analyser. The technique was found to be reliable even at RD as low as 20 pmol s-1. Error analysis showed that under normal operating conditions the coefficient of variation was approximately 3 %. With two operators, measurements could be made at the rate of one bud every four minutes. The ability to make non-destructive measurements has the advantage of enabling us to make sequential measurements on individual buds and monitor subsequent development. The system could be readily adapted to other woody fruit species, providing that gas-tight seals can be established on individual buds. Use of the system is illustrated by measuring the temperature response of the RD of dormant buds grown under contrasting conditions. All buds showed increasing RD with increasing temperature in the range 15 to 25 °C. Buds which had grown in the coolest region, where bud break is usually the earliest, had the highest RD when measured during early spring.
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  • 97
    ISSN: 1573-9058
    Keywords: Chlamydomonas ; chloroplast ; KCN ; Nicotiana ; photosystem 1 ; protoplast ; Synechococcus ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract By measuring the effect of cyanide on the flash-induced redox reactions of the cytochrome (cyt) b 6/f complex we carried out a comparative study in order to characterize the interaction between the photosynthetic and the respiratory electron transport systems in cyanobacterial (Synechococcus sp. PCC 6301) and green algal (Chlamydomonas reinhardtii) cells, and in tobacco (Nicotiana tabacum L. cv. Petit Havana SR1) protoplasts. We found that the addition of 1 mM KCN resulted in a significant acceleration of the rereduction-rate of cyt f +. This enhancement of the activity of the cyt b 6/f complex apparently occurred with the same mechanism in prokaryotes and eukaryotes, and its dependence on the concentration of KCN in eukaryotes ruled out an origin in mitorespiration, superoxide dismutase and plastocyanin, strongly suggesting that a cyanide-sensitive terminal oxidase, a putative component of chlororespiration, competes with photosystem 1 (PS1) for electrons from the plastoquionone (PQ) pool. Concerning the physiological role of the competition between the (chloro)respiratory and the photosynthetic electron transport systems, our data obtained with cyanobacterial and algal cells incubated at elevated temperatures (30–50 °C) showed that the respiratory control over photosynthesis became significant in cells exposed to heat-stress.
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  • 98
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    Nonlinear dynamics 9 (1996), S. 369-389 
    ISSN: 1573-269X
    Keywords: Damping ; vibration ; temperature ; sandwich
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract The paper studies the effects of a rapidly changed temperature on the free vibrations of simply supported sandwich plates. It has been taken into account that the properties of the facings and of the core of the sandwich plate change with the temperature. The effects of geometrical nonlinearities on the behaviour of the plate have also been included. The damping is considered by modelling the viscoelastic core as a Voigt-Kelvin solid. A Runge-Kutta method is employed to solve the governing equations and obtain the numerical results. It was found that the rapid change of temperature strongly affects the amplitude and frequency of the vibrations.
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  • 99
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    Journal of elasticity 44 (1996), S. 229-254 
    ISSN: 1573-2681
    Keywords: thermoelasticity ; surface ; nearly-planar ; dynamic ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The effects of non-planarity on the dynamic surface temperature changes induced for plane-strain and 3D problems on the nearly-planar surfaces of, respectively, coupled thermoelastic half-planes and half-spaces by surface heat fluxes are treated. The nearly-planar nature of the surfaces allows the problem solutions to be written, following a standard perturbation scheme, as series expansions in a dimensionless surface contour amplitude parameter. The first, or zero-order, terms represent the ideal (planar) surface solutions, while the second, or first-order, terms represent corrections for non-planarity. Because the characteristic thermoelastic time is of O(10−7)μs, large-time asymptotic forms of the exact integral transform solutions can be used. These can be inverted exactly and used in Green's function operations to yield analytic, or integrals of analytic, expressions. Two types of thermal loading for the half-plane and yet a third type of thermal loading for the half-space are considered. Comparison of the zero- and first-order surface temperature changes for each case indicate that non-planarity gives rise for large times to changes in surface regions beyond those predicted by an ideal surface analysis. Moreover, the magnitudes of these changes can be more significant than the ideal surface results.
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  • 100
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    Tribology letters 2 (1996), S. 263-272 
    ISSN: 1573-2711
    Keywords: wear ; temperature ; coatings ; Ni-P coatings ; lubrication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The effect of temperature on the wear of as-deposited electroless Ni-P coating under lubricated reciprocating sliding conditions has been investigated using the ball-on-block test method. It was shown that the temperature increase from 25 to 100°C reduces the lubricated wear of EN coatings, especially at high loads. The wear mechanism has also changed as the temperature rises from 25 to 100°C. X-ray mapping and EDS analyses have shown that there are more sulfur and phosphorus on the wear track at high temperature which may be responsible for reduced friction and the wear of the coating.
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