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  • 1
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 660-662 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We have studied the effects of high-temperature anneals on sequentially deposited TlBaCaCu films in an environment containing O2 and TlOx . From Auger electron spectroscopy depth profiles, it was found that Tl was quite volatile and can be easily eliminated from the thin films after a short treatment at 830 °C. However, the Tl can be incorporated in the films after appropriate treatment.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 58 (1987), S. 1937-1941 
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: A highly sensitive, adiabatic titration calorimeter controlled by a personal computer is described. Operation of the entire calorimetric titration is automated, including the thermoelectric offset of the heat of stirring, the electrical calibration of the heat capacity, the addition of titrant, and the measurement of the heat of reaction. The average uncertainty in heat measurements was ≈±0.003 J for titrant additions generating 0.025 to 1.0 J of heat change in a 50-ml sample. Calibration of the calorimeter using tris-(hydroxymethyl) aminomethane [TRIS] gave excellent agreement with previously published values.
    Materialart: Digitale Medien
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  • 3
    ISSN: 1520-5126
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 16 (1980), S. 0 
    ISSN: 1095-8649
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Juvenile Dover sole, Solea solea, were weaned from a live food, Artemia salina nauplii, on to a casein-based particulate diet flavoured with flesh of the mussel, Mytilus edulis. These fish would not accept an unflavoured casein-based diet but readily ate the diet flavoured with either mussel flesh or a mixture of pure chemicals whose composition was based on an analysis of the low-molecular weight fraction of mussel flesh. The rate of growth and survival over a seventy-seven day period was essentially the same on either of the flavoured diets. The active constituent in the mixture of pure chemicals was identified as glycine betaine for fish of wet weight exceeding 50g while glycine betaine with certain L-amino-acids was required for fish of about 2.5 g wet weight. These results are discussed in relation to the known feeding behaviour and food preferences of the wild Dover sole.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Journal of solution chemistry 18 (1989), S. 211-216 
    ISSN: 1572-8927
    Schlagwort(e): Thorium ; fluoride ; complexation ; enthalpy ; calorimetry ; ionic bonding
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Titration calorimetry has been utilized to study the aqueous solution chemistry of the Th4++F− system. Enthalpies of the first three complexation reactions have been measured at an ionic strength of 0.5M at 25°C, and corresponding entropy values have been calculated. Results for the first complex are in good agreement with an established electrostatic model of metal-fluoride bonding.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Oecologia 46 (1980), S. 55-62 
    ISSN: 1432-1939
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary (1) We report some effects of an annually variable and unpredictable rainfall upon Darwin's Finches on the Galápagos. Finch numbers, foraging and food supply were studied on I. Daphne Major in December of 1973 and 1977, and compared. 1973 was the second of two successive wet years and 1977 was a drought year. (2) Seed numbers and biomass were approximately one order of magnitude lower in the drought year than in the wet year. Small and soft seeds were absolutely and relatively rarer in the drought year than in the wet year. (3) Similarly finch numbers and biomass were approximately one order of magnitude lower in the drought year than in the wet year. Numbers of G. scandens declined less than did number of G. fortis. Both species exhibited unabalaced sex ratios, in favour of males, in the dry year in contrast to balanced sex ratios in the wet year. Male scandens were heavier on average in the wet year, but male fortis were heavier in the dry year. (4) The foraging of scandens, a cactus (Opuntia) specialist, was similar in the two years. The foraging of fortis in the dry year differed from foraging in the wet year in three important respects: fortis devoted a disproportionate amount of time to feeding on small seeds while tending to avoid seeds of Opuntia, they fed more on floral and extra-floral parts of Opuntia and they fed on Tribulus cistoides, a large and hard fruit which was absent from their diet in the wet year. As a consequence of feeding more on Opuntia, fortis foraging was more similar to scandens foraging in the dry year than in the wet year. (5) The results are discussed in relation to expectations from competition theory. The decline in numbers in relation to a decline in food supply was expected, but a convergence in diets was not. The convergence is attributed to the recent renewal of a single resource, Opuntia flowers, against a background of general resource scarcity. Diet overlap and limitation of numbers by food provide indirect evidence of interspecific competition; scandens, with an included niche, was competitively superior to fortis.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Oecologia 49 (1981), S. 179-187 
    ISSN: 1432-1939
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary (1) There is a close association between Opuntia helleri (cactus) and Geospiza conirostris (cactus finch) on Isla Genovesa, and between Opuntia echios and Geospiza scandens on Isla Daphne Major. The two finch species consume nectar and pollen, pollinate the obligatorily out-crossing flowers, consume the aril around the seeds, crack the seeds and occasionally disperse them. (2) In the dry season the two finch species open Opuntia flower buds, thereby gaining early access to pollen. But in the process, and at partially open flowers, they snip the style and destroy the stigmas in up to 78% of the flowers. (3) Stigma snipping prevents fertilization of the ovules and the development of seeds which are an important food item later in the year when food supply is likely to limit finch population sizes. Stigma snipping almost ceases in the main part of the wet season, corresponding with an increase in the density of Opuntia flowers and other food types, and a decrease in the proportion of feeding time spent on Opuntia flowers. Stigma snipping neither increased the time flowers remained open nor influenced nectar flow or the number and duration of subsequent visits to flowers by potential pollinators. This last result precludes the possibility that snipping is a means of marking the flower to signal a previous visit to the flower and pollen removal. (4) We conclude that the two finch species snip stigmas to facilitate removal of pollen from the central incurving stamens which are masked by the stigma in a closed or partially open flower. The finches gain a short-term benefit from the removal of stigmas in easy access to pollen and possibly nectar. They potentially suffer in the long term through diminished dry season food supply (seeds), particularly in drought years but we were unable to detect any fitness decrement suffered by the individual finches which do the snipping. (5) An important implication of these results and interpretations is that a behavioral trait which confers a short-term benefit to the individual may increase the chances of the population going extinct.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Oecologia 58 (1983), S. 76-83 
    ISSN: 1432-1939
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary In this study we investigated the relationship between food availability, feeding ecology and territoriality in a population of Cactus Finches, Geospiza scandens, on Isla Daphne Major, Galápagos, between 1979 and 1981. We monitored the phenologies of the principal food types on the island and related them to changes in the feeding ecology of G. scandens. Feeding patterns closely tracked the availability of resources, with a similar pattern in each of the three years. Birds relied heavily on Opuntia fruits in the dry season. G. scandens defends year-round territories based on Opuntia. Variation in Opuntia phenologies between individual territories and between years was documented in order to provide a measure of territory quality over the three years. A correlation was demonstrated between the area of cactus within a territory and mating success of the owner. We suggest that territory quality also affects the survival of the owners during periods of food scarcity and that the mating and survival advantage of a high-quality territory occur at different times and to different degrees in different years. Hence the importance of territorial quality can only be judged over a long-term period in these long lived and sedentary birds.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Diabetologia 29 (1986), S. 405-406 
    ISSN: 1432-0428
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    ISSN: 1432-0428
    Schlagwort(e): Hypoglycaemia ; diabetes ; skin blood flow ; arteriovenous anastomoses ; thermoregulation ; vasopressin ; adrenaline ; laser doppler flowmetry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Body temperature falls during hypoglycaemia, perhaps as a protective mechanism. To test the hypothesis that the skin blood flow response to hypoglycaemia is specifically designed to facilitate heat loss we studied both nutritional blood flow and arteriovenous shunting of blood in skin during prolonged, controlled hypoglycaemia in man. We studied eight otherwise healthy, male, Type 1 (insulin-dependent) diabetic patients. Under Biostator control blood glucose was clamped at 8.0 (7.9–8.9), mmol/l (median and range) for 30 min, reduced to symptomatic hypoglycaemia, 1.7 (1.0–2.6) mmol/l for 20 min then raised to 4.9 (3.3–6.7) mmol/l. Interdigital skin web blood flow (laser doppler flowmeter, nutritional flow) fell during hypoglycaemia from 3.1 (2.2–3.8) to 2.4 (1.2–2.8) volts and remained depressed. In contrast, finger blood flow (venous occlusion plethysmography, arteriovenous shunt flow) started high at 54.7 (17.4–85.6), remained high at 52.7 (38.1–81.4) during hypoglycaemia but fell sharply to 25.3 (4.2–66.2) ml · min−1 · 100 ml−1 when symptoms were relieved. Plasma adrenaline and vasopressin both rose during hypoglycaemia from 0.4 (0.05–0.8) to 4.5 (2.3–20.2) nmol/l and from 0.5 (0.5–3.5) to 4.4 (2.0–13.9) pg/ml, respectively, and both fell sharply thereafter. Thus, the high skin blood flow observed during hypoglycaemia in man is due to arteriovenous shunting of blood and is consistent with a thermoregulatory mechanism.
    Materialart: Digitale Medien
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