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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 24 (1976), S. 219-236 
    ISSN: 1432-1106
    Keywords: Inferior olive ; Cerebellum ; Opossum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Although degeneration techniques suggest that cerebello-olivary fibers are limited in their origin and distribution, horseradish peroxidase and autoradiographic experiments make it clear that they arise within all cerebellar nuclei and project to most, if not all, areas of the contralateral inferior olive. Autoradiographic preparations show that cerebello-olivary fibers are highly ordered and suggest that the dentate nucleus projects primarily to the principal olive, the interpositus anterior relays particularly heavy to the dorsal accessory nucleus and the interpositus posterior distributes extensively to the medial accessory complex. Evidence for a small projection from the fastigial nucleus to the caudal medial accessory nucleus is also available. However, it appears clear that neither the dentate nor the interpositus nuclei project to just one subdivision of the olive. For example, although dentate fibers end extensively within the principal nucleus some of them also distribute to portions of the medial accessory nucleus and perhaps the dorsal accessory nucleus as well. The medial accessory olive is particularly complex and at rostral levels receives input from both interposed and dentate nuclei, whereas more caudally it receives a projection from the fastigial nucleus. Olivary fibers from both the interposed and dentate nuclei traverse the brachium conjunctivum descendons and distribute primarily to the rostral 2/3 to 3/4 of the olive, whereas those from fastigial neurons take a different route and end more caudally. Experiments utilizing horseradish peroxidase as a retrograde tracer suggest that cerebello-olivary fibers from both the interpositus anterior and dentate nuclei take origin from a population of generally small neurons.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 22 (1975), S. 13-24 
    ISSN: 1432-1106
    Keywords: Inferior olive ; Spinal afferents ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Identification of the direct spinal areas (portions of the dorsal and medial accessory nuclei) within the opossum inferior olivary complex was accomplished by mapping the location of the terminal degeneration by the Fink-Heimer technique subsequent to cervical cord lesions. Following similar lesions, sampling of these same regions for electron microscopic study was assured by examination of transversely oriented, 1 μ plastic sections prior to thin sectioning. The first evidence of electron dense axon terminals was found at a survival time of 24 hours. At survival times of 36, 48 and 72 hours, degenerating presynaptic profiles shrink, become irregular in shape and are totally or partially surrounded by glial processes. Spinal terminals average 1–2 μ in their greatest dimension, contain round, clear synaptic vesicles and generally contact small diameter (0.4–1.8 μ) dendritic shafts or occasional spiny appendages. The spiny dendritic appendages make up the central core of the olivary glomeruli and these juxtaposed dendritic processes exhibit gap junctions. At longer survival times (5, 7 and 9 days) many presynaptic profiles with either round or pleomorphic synaptic vesicles remain normal in appearance and contact dendritic shafts or the spiny appendages within glomeruli. Afferents from other sources (possibly including intrinsic neurons) must terminate within the direct spinal portion of the nuclear complex to account for the numerous axon terminals which retain normal morphology after such long survival times.
    Type of Medium: Electronic Resource
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 26 (1976), S. 159-170 
    ISSN: 1432-1106
    Keywords: Inferior olive ; Cerebellum ; Deep cerebellar nuclei ; Ultra-structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Section of the superior cerebellar peduncle just rostral to the deep cerebellar nuclei results in degenerating axon terminals within the contralateral inferior olive. The nuclear origin of this fiber system and its distribution within the subdivisions of the inferior olive were described in a companion study (Martin et al., 1976). Precise localization of these degenerating terminals within the nucleus was accomplished by the examination of 1 μ plastic sections cut from each tissue block prior to thin sectioning. Degenerating axon terminals are present in all the nuclear subdivisions and when seen with the electron microscope they frequently are localized in the previously described synaptic clusters (King, 1976). These terminals demonstrate an electron dense reaction at survival times of 2 and 3 days. By day 4, they are shrunken and irregular in shape, and typically are surrounded by astrocyte processes. Cerebello-olivary axon terminals measure 1–3 μ, contain spherical, clear synaptic vesicles and typically contact spiny appendages within the synaptic clusters (glomeruli). Thus, we have demonstrated that one of the primary axon systems which terminates within the synaptic clusters is from the cerebellar nuclei. We have yet to determine the origins of the remaining terminals within the synaptic clusters which include endings with either smaller spherical, pleomorphic or numerous dense core vesicles.
    Type of Medium: Electronic Resource
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  • 14
    Electronic Resource
    Electronic Resource
    Cambridge : Cambridge University Press
    Journal of Latin American studies 10 (1978), S. 395-396 
    ISSN: 0022-216X
    Source: Cambridge Journals Digital Archives
    Topics: Political Science
    Type of Medium: Electronic Resource
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  • 15
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 34 (1979), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: A cutting experiment was carried out on a sward of S23 perennial ryegrass to study the effect of different defoliation regimes on regrowth and the factors affecting regrowth. The defoliation frequencies and intensities encompassed the range commonly found on continuously stocked pastures. The defoliation regimes produced swards of contrasting growth form with regrowth characteristics which differed in respect of senescence loss, fall in water-soluble carbohydrate concentration, residual leaf area index, photosynthesis per unit leaf area index and photosynthesis per unit area of land. Regrowth was most closely related to the latter. These results were used to interpret data for net canopy photosynthesis of continuously grazed pastures.
    Type of Medium: Electronic Resource
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  • 16
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 33 (1978), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Single plants of white clover (Trifolium repens) were subjected either to two intensities of overall defoliation or to severe defoliation of different parts of the plant. Measurements were made of growth in terms of leaf size, petiole length, internode length and other parameters, and compared with those of undefoliated plants. The results show that, while growth of all parts of the plant was reduced by severe overall defoliation, partial defoliation affected various parts of the plant differently according to which leaves were removed. The results are interpreted in terms of the acropetal movement of assimilates from alternative sources in response to defoliation.The probable effects of this on yield and its relevance to grazing management of newly seeded clover are discussed.
    Type of Medium: Electronic Resource
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  • 17
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Grass and forage science 34 (1979), S. 0 
    ISSN: 1365-2494
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: An apparatus in which shoot and root CO2 exchange and acetylene reduction can be simultaneously measured in specific white cloverrhizobium associations is described. In mature stolonating clover there was a fairly constant ratio between net photosynthesis, root respiration and acetylene reduction. Of the net carbon fixed daily (12 h light of 80 W m-2, 400–700 nm; day/night temperature 15°C) 12% was lost during the dark period by the shoot and 17% by the nodulated root. Changes in the rate of acetylene reduction by nodulated root systems occurred more slowly than those in rates of root respiration in response to reduced irradiance. In 21·5 h continuous darkness the rate of acetylene reduction remained constant. Responses to increased irradiance were more immediate in both root respiration and acetylene reduction. In plants maintained at 15°C in a 12-h, 80-W m-2 photoperiod there was no significant diurnal variation in acetylene reduction or root respiration. Acetylene depressed root respiration by 20%. Assuming the energy requirement of the nitrogenase system to be the same when reducing acetylene and N the depression can be used as an indication of the energy requirement of fixed N assimilation, metabolism and export in the nodulated root. Of the net carbon fixed daily 3·4% was utilized in this way in plants growing in a 12-h photoperiod (80 W m-2, 400–700 nm) at 15°C.
    Type of Medium: Electronic Resource
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  • 18
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Plant pathology 26 (1977), S. 0 
    ISSN: 1365-3059
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Samples from 265–333 randomly selected crops of winter wheat in England and Wales were taken annually from 1970 to 1975 after heading, the main sample being at the milky-ripe growth stage. The percentage of the area of the top two leaves affected by diseases was recorded and, in the last five years, samples were tested for infection by barley yellow dwarf virus: in 1975 stem base diseases were recorded. Scptoria was the most common and severe disease in four of the six years. In. 1970 mildew was most severe and, in 1975, brown rust. The severity of infection by Septoria tended to be greater in southern and western areas in wetter summers and in crops following a previous cereal. Yellow rust was most severe in 1972, when it was very prevalent on cv. Joss Cambier. In 1973 the disease was less severe, but in 1974 and 1975 the severities of both yellow and brown rusts increased in association with the popularity of susceptible cultivars. There was a tendency for yellow rust to be more severe on early-sown crops. In 1975, eyespot was recorded on 11·8 per cent of the stems. 1·8 per cent of the symptoms being severe. Fungicidal sprays were associated with a slightly smaller incidence of stem base diseases. Estimates of percentage loss in yield due to particular diseases vary from almost zero caused by yellow rust in 1970 to 7·4 per cent loss caused by Septoria in 1972.
    Type of Medium: Electronic Resource
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  • 19
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Plant pathology 25 (1976), S. 0 
    ISSN: 1365-3059
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: In observations made over four seasons, counts of brown rust spores trapped above barley crops and infections of healthy plants placed within crops, indicated that there was a high risk of infection on days when at least 5 far of dew were recorded following a day on which the maximum temperature was greater than 15°C. In spray-timing trials, the fungicidal sprays applied between the first appearance of brown rust in the crop and the beginning of the exponential phase of the epidemic usually were associated with the highest yields. The relationships between levels of brown rust and yields in these trials is discussed in connection with their relevance to the estimation of losses caused by the disease.
    Type of Medium: Electronic Resource
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  • 20
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Plant pathology 26 (1977), S. 0 
    ISSN: 1365-3059
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: In field experiments with winter wheat in Hertfordshire, seed infection with Septoria nodorum and the incorporation of infected straw into seedbeds were often correlated with reduced seedling establishment and increased seedling infection. Artificially infected straw was a less effective source of inoculum than naturally infected straw, which gave rise to the most severe leaf symptoms in one season when heavy rain favoured the development of an epidemic. In an experiment where a severe epidemic did not develop, organomercury seed treatment was the most important factor increasing seedling emergence and grain yield, also apparently leading to decreased Septoria infection of the flag leaf sheath. Spores from lesions which developed after plots were sprayed with a suspension of pycnidiospores of S. nodorum were not always morphologically typical of that species.
    Type of Medium: Electronic Resource
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