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  • 1980-1984  (14)
  • 1955-1959
  • 1930-1934
  • 1915-1919
  • 1983  (14)
  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Scandinavian journal of immunology 18 (1983), S. 0 
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Cultured human monocytes activated in vitro with lymphokines and lipopolysacchuridc release cytostatic protein factors that may be separated by ion-exchange chromatography into two populations, termed cytostatic factors I and II (CF I and II). The effect of CF I and II on target cell DNA synthesis, protein synthesis, and ATP content and the possible presence of a CF-associated protease activity were investigated. Inhibition of DNA synthesis was detected 4 h after addition of either CF I or CF II, whereas inhibition of protein synthesis was first detected after 10-15 h. Moreover, 20 h after addition of either CF I or CF II the average DNA synthesis per cell was inhibited by 25–35%, as compared with 10–15% inhibition of protein synthesis. No significant alteration in cellular ATP content was observed in cells culture, up to 25 h with either CF I or CF II. Thus, neither protein synthesis nor generation of ATP appeared to be primary targets of either CF I or CFII, but the factors may act more directly on DNA synthesis. Protease activity was not associated with either CF I or CF II, and the factors thus differed from a previously reported cytolytic protease released from activated murinc macrophages.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The question whether scalar-type interactions contribute to weak interactions at large momentum transfer has been investigated by a measurement of the longitudinal polarization of positive muons produced in charged-current interactions of high-energy antineutrinos with iron. At an average momentum transfer 〈Q 2〉=4 GeV2 the muon spin is found to be oriented forward with respect to the muon momentum vector, with an average polarization of 1.10±0.24, consistent with positive helicity. A limit on scalar contributions of σs, p/σtot 〈7% at the 95% confidence level can be deduced. A search for violation of time reversal invariance which could manifest itself by a polarization component perpendicular to the muon production plane gave a limit of σtv/σtot 〈16% (95% c.l.). It is concluded that the weak leptonic charged current retains its dominant vector and axial vector structure at large momentum transfers.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Measurements of energy moments for single quark jets at c.m. energies between 12 and 31.6 GeV are presented. The data, corrected for detector effects and initial state radiation, are compared to QCD predictions in the leading log approximation. Non perturbative effects are found to be moderate, and they strongly decrease with increasing c.m. energy. Once partly corrected for the presence of these fragmentation effects, our data agree well with all features of the leading log prediction, and in particular with the variation of the strong coupling constant over a wide range of energies and momentum transfers.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The reactione + e −→μ + μ − has been studied with the PLUTO detector at the c.m. energy of 34.7 GeV, based on an integrated luminosity of 46 pb−1. The total cross section agrees with QED predictions, and the corresponding lower limits for theΛ + andΛ − QED cutoff parameters are 267 and 126 GeV respectively (95% c.l.). A forward-backward asymmetry parameterA=−(13.4±3.1±〈1)% is observed, which is in agreement with the standard model, as well as with other PETRA results obtained at the same energy.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Urological research 11 (1983), S. 117-120 
    ISSN: 1434-0879
    Keywords: E. coli ; Epididymis ; Epididymitis ; Dymphatic system ; Testicular inflammation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The injection of E. Coli into the tail of the epididymis in the rat caused epididymitis. In 20% of the cases, the inflammation is spread through the lymphatic system to the testis. The germinal cells are destroyed in 50% of the cases by the second day, and are not reestablished for several months. Signs of testicular inflammation are not found. The destruction seems to be caused by E. Coli toxins, as shown by injections of killed bacteria.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Irrigation science 4 (1983), S. 31-44 
    ISSN: 1432-1319
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A three year field experiment was conducted to establish the salt tolerance of corn in the Sacramento-San Joaquin Delta of California. The study was essential because of the grave consequences of allowing the surface waters in the Delta to become excessively saline and the absence of salt tolerance information on organic soils. The relative yield (Y r) of corn grain was found to be related to soil salinity (the average electrical conductivity of soil water in the root zone during the growing season, $$\overline {EC}$$ sw ) by Y r=100−14 ( $$\overline {EC}$$ sw−3.7) when $$\overline {EC}$$ sw ≧3.7. Below an $$\overline {EC}$$ sw of 3.7 dS/m, grain yield was equivalent statistically to nonsaline conditions. As $$\overline {EC}$$ sw . exceeded the threshold value of 3.7 dS/m, Y r was reduced at the rate of 14%/(dS/m). Excess salinity reduced yield by reducing both kernel mass and, to a lesser extent, plant density. An almost identical relationship was found between $$\overline {EC}$$ sw , and total shoot growth on a relative basis. Thus, to prevent loss in corn yield, the salinity of the applied water and management practices (including irrigation timing, irrigation amount, and leaching) must prevent $$\overline {EC}$$ sw from exceeding 3.7 dS/m, on the average, during the growing season.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 153 (1983), S. 29-37 
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Sternopygus dariensis, a weakly electric gymnotiform fish, possesses sexually different electric organ discharges (EODs), with females emitting EODs at higher frequencies than males. This difference can be accounted for by the effects of gonadal steroids: laboratory experiments indicate that daily injections (0.25 to 20 μg/g body weight) of androgens lower discharge frequencies while injections of estrogens raise discharge frequencies. Clear changes in discharge frequencies can be noted over the course of days, and persist until several days after injections are terminated. These effects are noted irrespective of age or sex, and can be seen in both intact and gonadectomized animals. The discharge frequencies of these animals are established by a neuronal oscillator, the medullary pacemaker nucleus. Thus, the steroid-elicited changes in discharge frequencies are indicative of changes in the activity of the pacemaker nucleus. Steroids may be exerting their effects either through indirect effects upon those neurons which provide input to the pacemaker, or through direct effects upon the spontaneous depolarizations of the pacemaker itself.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 151 (1983), S. 401-406 
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electric fish locate objects in their environment by sensing the distortions which such objects cause in the electric field of their own electric organ discharge (EOD). Extraneous electrical signals, such as discharges of other electric fish, are a potential source of confusion. Behavior experiments with artificial EODs indicate that fish of the family Mormyridae minimize such interference by gating electrosensory input. Input is only considered relevant if it arrives during a brief period after the motor command which elicits the normal EOD. These results confirm an earlier physiologically-based hypothesis that a corollary discharge mechanism assures preferential access to the electrolocation system for sensory input elicited by an animal's own EOD.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 153 (1983), S. 477-487 
    ISSN: 1432-1351
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The tuning of electroreceptors inSternopygus was studied in control fish and in fish injected with 5α-dihydrotestosterone (DHT). DHT has been shown to cause long-term decreases in electric organ discharge (EOD) frequencies of this species (Meyer 1983), an effect which may underlie naturally occurring ontogenetic changes in EOD frequencies. As determined by impulse-evoked receptor oscillations and single unit recordings of primary electroreceptive afferents in untreated fish, electroreceptors of an individual fish are narrowly tuned to frequencies close to the EOD frequency of that animal. Sixty-six percent of all units had best frequencies (BF)s higher than the EOD frequency. Sharpness of tuning (Q1odb) was found to vary with the distance of the BF from the EOD frequency in each individual, and less so with BF proper: units with BFs above EOD frequency were more sharply tuned than those with BFs below. After treatment with DHT, along with expected decreases in EOD frequency, receptor oscillation frequencies and single unit BFs decreased and approached the new frequency of the EOD. DHT injections had no effect on unit thresholds, the sharpness of tuning, or the distribution of best frequencies around a given animal's mean best frequency. Units with higher BFs within a sample from an individual still tended to be the most sharply tuned. EOD frequency and mean recorded electroreceptor BF changed at approximately the same rate, although the change in receptor tuning lagged behind changes in EOD frequency. Thus, the tuning mechanism of electroreceptors in this species is labile, and this lability allows the electroreceptors to maintain their frequency sensitivities close to the naturally-changing values of the EOD frequency.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Irrigation science 4 (1983), S. 71-80 
    ISSN: 1432-1319
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The Delta is an important agricultural area containing organic soils that are threatened by salinity. To aid in water allocation and management decisions, the maximum salinity level in irrigation water that preserves agricultural production was estimated from data gathered in a field trial to establish the salt tolerance of corn. All of the physical properties measured indicated that the soil under study was typical of organic soils in the Delta and elsewhere. Differences in soil sample preparation were shown to influence salinity measurements from the subsoil. Samples brought to saturation without either grinding or drying gave electrical conductivity measurements in agreement with those for soil water extracted by suction cups. Above average rainfall and water table control during the winter effectively leached the upper soil profile. The ratio between the average electrical conductivity of the soil water in the root zone ( $$\overline {EC}$$ sw ) and the salinity of the irrigation water (EC i) was found to be a function of EC i and not constant. Under present conditions of low EC i (0.2 to 0.8 dS/m) and with normal winter rainfall $$\overline {EC}$$ sw /EC i is about 8. As EC i increases, however, the ratio decreases. At the soil water salinity threshold for corn grain (3.7 dS/m), the average ratio is 1.7 which results in a maximum value of 2.2 dS/m for EC i without yield loss under normal conditions. With subirrigation and below normal rainfall, as in 1981, the maximum value of EC i would be 0.8 dS/m.
    Type of Medium: Electronic Resource
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