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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of marital and family therapy 24 (1998), S. 0 
    ISSN: 1752-0606
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Psychology
    Notes: This is a critical review of live supervision with emphasis on technical innovations such as earphones or bug-in-the-ear, Teleprompters, and computers. A computer-assisted approach is described that overcomes many criticisms of live supervision. Direct supervision uses a computer monitor to unobtrusively provide information to the therapist about the supervisor's perceptions of the clients' and therapist's behavior, the expected therapeutic behaviors, and the therapist's “on target” behavior. Direct supervision has the advantage over other forms of supervision by providing an immediate, continuous, and permanent record for postsession supervision and for research into the supervisor-therapist-client process. The paper provides several suggestions for research.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Rheologica acta 34 (1995), S. 360-383 
    ISSN: 1435-1528
    Keywords: Steady state planar flows ; tube model ; constitutive equation ; universal tensor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract Numerical predictions of the Doi-Edwards tube model with segmental stretch and a freely jointed chain spring model are presented for steady two-dimensional flows with a continuously varying degree of extensional and shear character. Our results are obtained from three sets of calculations by considering the effect of the flow-type parameter, the molecular weight and the number of entanglements per chain on the model predictions. The predicted degree of stretch and orientation, as well as specific rheological and optical properties that can be measured experimentally are presented. As anticipated, calculations reveal that the ‘orientational’ dynamics are controlled by the reptative tube disengagement process, whereas the stretching process is controlled by the Rouse dynamics. Inclusion of segmental stretch fundamentally alters the character of the Doi-Edwards model. Calculations reveal that as the flow becomes increasingly extensional in character, significant steady state stretch is predicted with a commensurate modification of the material functions. According to calculated results, it is possible to have significant chain stretching without producing measurable changes in the stress optical coefficient.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Rheologica acta 34 (1995), S. 339-359 
    ISSN: 1435-1528
    Keywords: Tube model ; segmental stretch ; constitutive equation ; molecular model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract The Doi-Edwards model with segmental stretch and a non-linear finitely extensible spring law is described and examined in simple flow situations where analytic results are derivable; namely oscillatory flow and steady state flow at high deformation rates. The model is shown to be consistent with the Bueche-Ferry hypothesis in fast large strain unidirectional flows but to violate this rule in small strain reversing flows. The discrepancy is identified with a preaveraging approximation used to describe the relative tube-chain velocity. Experimentally verifiable scaling rule for the birefringence as a universal function of a planar flow-type parameter and deformation rate are identified. Sensitivity to the extensional flow character, absent in the original tube model, manifests itself with the introduction of segmental stretch. Although the model generates a non-separable memory function kernel the deformation dependence of the memory function is quantitatively shown to have negligible impact on the predicted theological properties relative to the original Doi-Edwards model. With this simplification, relatively uncomplicated approximations to the segmental stretch model can be deduced.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1572-9680
    Keywords: water balance ; Pinus radiata ; Lolium perene ; Medicago sativa ; Trifolium spp ; rainfall interception ; competition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In this study we determined soil moisture storage, evapotranspiration (ET) and light interception in an agroforestry trial consisting of pine trees grown over (1) control (bare ground), (2) ryegrass/clovers (Lolium perene/Trifolium spp.), (3) lucerne (Medicago sativa), and (4) ryegrass only during the third growing season between 1992 and 1993. The results show that: 1. In the period when rainfall was frequent and exceeded the evaporative demand (Epot), ET and depletion of soil moisture were not affected by the ground cover treatments. During summer when rainfall was less frequent, but with moisture readily available in the soil profile, ET was associated with plant canopy, and was significantly higher for the pasture ground covers than for the control. Therefore, the more rapid growth by lucerne caused higher ET in this ground cover than in the ryegrass/clovers ground cover in which the pasture was slow growing. At the end of the study period, total ET was in the following order: lucerne (757 mm) 〉 ryegrass/clovers (729 mm) 〉 Control (618 mm). 2. ET was dominated by pasture transpiration (Ep) during most of the growing season, but by tree transpiration (Et) in winter when large parts of the pasture canopy was shaded. Ep was always at least 16% higher for lucerne than for ryegrass/clovers species as a result of a greater radiation intercepted by the former. 3. Fraction of incoming radiation intercepted by the tree crowns was in the following order: control 〉 ryegrass 〉 ryegrass/clovers 〉 lucerne. At the end of the one-year period, fraction of intercepted radiation was 140% greater for control than for lucerne ground cover. 4. The control produced the largest tree crowns, which were almost twice the tree crowns in the lucerne ground cover which produced the smallest trees. Accordingly, the trees in the control intercepted more radiation and rainfall, with the former being lost to evaporation, than the trees in the pasture. 5. The fractions of radiation intercepted and ET accounted for by the trees and pastures were associated with the proportion of the plot area they occupied.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1572-9680
    Keywords: competition ; water use efficiency ; radiation use efficiency ; land equivalent ratio
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In this paper we analyzed the dry matter yields (DM) produced in an agroforestry trial consisting of pine trees grown over (1) Control (bare ground), (2) ryegrass/clovers (Lolium perene/Trifolium spp.), (3) ryegrass only, and (4) lucerne (Medicago sativa) during the third growing season between 1992 and 1993. In addition these pastures were grown alone in separate plots in the open. The results show that: 1. Pasture yields during the one-year period in the agroforestry plots were little affected by the presence of trees although there were seasonal trends: yields were generally unaffected or increased in summer, but reduced in spring as a result of tree shade. Total pasture yield during the one-year period was in the following order: lucerne 〉 ryegrass/clovers 〉 ryegrass. This trend was the exact opposite of that shown by the above-ground tree weight which was reduced in the pasture ground covers by between 16 and 52%. The reduction in tree weights was associated with reduced soil moisture availability arising from competition with the pasture species. Thus the relationship between the yields of trees and pasture species in the agroforestry plots was reciprocal. 2. The combined DM for both the trees and pastures in the agroforestry plots during the one-year period was in the following order: lucerne (20 t ha−1) 〉 ryegrass/clovers (16 t) 〉 ryegrass (11 t) 〉 control (6 t) which was consistent with the total water used and photosynthetically active radiation (PAR) intercepted. The trees accounted for 55, 44, 34 and 24% of water used respectively in control, ryegrass, ryegras/cclovers and lucerne ground covers. The balance was largely accounted for by pasture transpiration, except in the control where soil evaporation was significant. The fraction of intercepted PAR accounted for by the trees followed a similar trend to that of the water used. 3. The crop coefficient for water use efficiency (k) (Pa) was 2.3 for radiata pine, 3.6 for ryegrass/clovers, 2.8 for ryegrass and 4.8 for lucerne. The DM produced per unit of water used (kg mm−1 ha−1) during the one-year period was 24.5 for radiata pine, 41.1 for lucerne, 30.0 for ryegrass/clovers and 23.1 for ryegrass. Radiation use efficiency (g DM MJ−1 m−2) was 1.33 for pine, 1.83 for ryegrass/clovers, 1.49 for ryegrass and 2.34 for lucerne. 4. The land equivalent ratio (LER), i.e. the sum of ratios of DM produced by the plant species in the agroforestry plots to those produced in the sole plots, was 1.95 for ryegrass, 1.71 for ryegrass/clovers and 1.45 for lucerne ground covers. 5. These results indicate the susceptibility of pasture species to shading and interception of rainfall by the tree crowns (aboveground interactions), and the trees to competition for soil moisture (underground interaction).
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1572-9680
    Keywords: nitrogen fixation ; 15N ; %Ndfa ; ryegrass+clover pasture ; silvopastoral system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Quantitative field measurements of biological nitrogen fixation (BNF) and biomass production by four different understorey pastures in a Pinus radiata-pasture agroforestry system were determined over a period of one year. The trees were two years old at the beginning of this study and the understorey pastures were being cut and removed for silage. The BNF was determined using the 15N dilution technique. Pastures of ryegrass+clover, cocksfoot+clover, phalaris+clover and lucerne were used. Substantial amounts of BNF were found (71 to 230 kg N ha−1 year−1) with lucerne showing the highest N fixation. However, lucerne derived only 71 to 72% of its N from the atmosphere (%Ndfa) during the spring/summer period compared to 83–97% with clovers, thus the net N demand from the soil was substantially higher with lucerne. This caused increased N stress to the trees. Clover in ryegrass+clover pasture fixed more N than the other grass+clover pastures. Although pasture position in relation to trees did not affect annual pasture total DMY and %Ndfa, pastures north of tree row grew better than those in other positions. Trees significantly affected the BNF of legumes and the botanical composition of pastures with highest BNF and legume production occurring in pastures midway between two rows of trees. These results suggest that it would be advantageous to evaluate different legumes and grasses for tolerance of shade and moisture stress in future studies. As the trees studied were only 1.5 to 3 m in height, their effects on BNF, seasonal pasture biomass production and botanical composition are expected to increase with tree dominance in the ecosystem with time. Amounts of N fixed were related to the productivity (i.e. dry matter and N yield) and seasonal persistence of the legumes. The productivity was high in spring and summer and low in autumn and winter.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1572-9680
    Keywords: silvopastoral ; shelterbelts ; woodlots ; amenity plantings ; erosion control ; conservation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Agroforestry in Australia and New Zealand is dominated by silvopastoralism. Farmers may employ combinations of shelterbelts, shade trees, widely spaced trees over pasture, or more densely planted woodlots. In addition to wood production and shelter, erosion control, amenity and landscape planting, and conservation of natural forest are often important. Many farm forestry people show considerable innovation. In temperate wetter areas of Australia, eucalyptus and, to a lesser extent,Pinus radiata (radiata pine) dominate agroforestry tree plantings for wood, shade, shelter, and salinisation and erosion prevention. The One Billion Tree Program, initiated by the Australian Federal Government, provides limited funding for tree planting. Joint farmer ventures with the State or local industry are also common. Most State governments also provide advice, and planting is tax deductible. Local landcare groups, formed to encourage sustainable agriculture, often promote tree planting, particularly where soil degradation is a problem. Melbourne University and other Techncial Institutes offer training in agroforestry. In New Zealand, a third of the farms require trees for soil conservation. This, together with the growing recognition of the financial benefits of planting trees, has resulted in small landowners doing most of the current planting of 80,000 to 100,000 ha yr−1. Most farmers plant radiata pine, but eucalyptus and other hardwoods, including willows and poplars, are also widely used. There are almost no government incentives for tree planting in New Zealand. The Farm Forestry Association is the major extension organization. Lincoln University has an important teaching and research commitment, and the New Zealand Forest Research Institute Limited has developed very useful management models.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 57 (1995), S. 151-173 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Homogeneous and nonhomogeneous reactive extrusion of polypropylene is modeled using random chain scission statistics coupled with the double reptation mixing rule. In this manner, the evolution of both the molecular weight distribution and the linear viscoelastic material properties is quantitatively predicted for the reactive extrusion-pelletization process. Dispersion in the level of random chain scission has little impact on the MFI for a given average level of chain scission; however, dispersion does generate a marked increase in the recoverable compliance (melt elasticity) relative to the ideal homogeneous random chain scission case. Methods to quantitatively determine the degree of cracking dispersion in processing equipment are identified. Quality control issues such as blending materials of known linear viscoelastic properties to obtain a desired property set is considered in the context of known empirical relations consistent with the double reptation model. Simple mixing rules for the melt flow index and the steady-state recoverable compliance involving only single component MFI and Je information are derived. © 1995 John Wiley & Sons, Inc.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
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