8,851 research outputs found
The effects of organic farming on the soil physical environment
The aim of this research was to investigate the effects of organic farming practices on the development of soil physical properties, and in particular, soil structure in comparison with conventional agricultural management. The soil structure of organically and conventionally managed soils at one site was compared in a quantitative manner at different scales of observations using image analysis. Key soil physical and chemical properties were measured as well as the pore fractal geometry to characterise pore roughness. Organically managed soils had higher organic matter content and provided a more stable soil structure than conventionally managed soils. The higher porosity (%) at the macroscale in soil under conventional management was due to fewer larger pores while mesoand microscale porosity was found to be greater under organic management. Organically managed soils typically provided spatially well distributed pores of all sizes and of greater roughness compared to those under conventional management. These variations in the soil physical environment are likely to impact significantly on the performance of these soils for a number of key processes such as crop establishment and water availabilit
Model based methodology development for energy recovery in ash heat exchange systems
Flash tank evaporation combined with a condensing heat exchanger can be used when heat exchange is required between two streams and where at least one of these streams is difficult to handle (in terms of solid particles content, viscosity, pH, consistency etc.). To increase the efficiency of heat exchange, a cascade of these units in series can be used. Heat transfer relationships in such a cascade are very complex due to their interconnectivity, thus the impact of any changes proposed is difficult to predict. In this report, a mathematical model of a single unit ash tank evaporator combined with a condensing heat exchanger unit is proposed. This model is then developed for a chain of the units. The purpose of this model is to allow an accurate evaluation of the effect and result of an alteration to the system. The resulting model
is applied to the RUSAL Aughinish Alumina digester area
Highly electronegative metallic contacts to semiconductors using polymeric sulfur nitride
The Schottky barriers formed on n‐ZnS and n‐ZnSe by polymeric sulfur nitride have been compared to barriers formed by Au. Barrier energies as determined by photoresponse, current‐voltage, and capacitance‐voltage methods show that (SN)_x is approximately 1.0 eV higher than Au on n‐ZnS and 0.3–0.4 eV higher than Au on n‐ZnSe. We believe that this is the first report of any metallic contact more electronegative than Au
HgSe, a highly electronegative stable metallic contact for semiconductor devices
Schottky barriers formed by the highly electronegative substance HgSe on n-ZnS and on n-ZnSe have been characterized by capacitance-voltage and photoresponse measurements. The barriers are about 0.5 eV greater than Au barriers on these n-type substrates. HgSe contacts are stable under ambient conditions and are easily fabricated, making them attractive for device use
Masses, luminosities and dynamics of galactic molecular clouds
Star formation in galaxies takes place in molecular clouds and the Milky Way is the only galaxy in which it is possible to resolve and study the physical properties and star formation activity of individual clouds. The masses, luminosities, dynamics, and distribution of molecular clouds, primarily giant molecular clouds in the Milky Way are described and analyzed. The observational data sets are the Massachusetts-Stony Brook CO Galactic Plane Survey and the IRAS far IR images. The molecular mass and infrared luminosities of glactic clouds are then compared with the molecular mass and infrared luminosities of external galaxies
Root anatomical traits contribute to deeper rooting of maize under compacted field conditions
© The Author(s) 2020. To better understand the role of root anatomy in regulating plant adaptation to soil mechanical impedance, 12 maize lines were evaluated in two soils with and without compaction treatments under field conditions. Penetrometer resistance was 1–2 MPa greater in the surface 30 cm of the compacted plots at a water content of 17–20% (v/v). Root thickening in response to compaction varied among genotypes and was negatively associated with rooting depth at one field site under non-compacted plots. Thickening was not associated with rooting depth on compacted plots. Genotypic variation in root anatomy was related to rooting depth. Deeper-rooting plants were associated with reduced cortical cell file number in combination with greater mid cortical cell area for node 3 roots. For node 4, roots with increased aerenchyma were deeper roots. A greater influence of anatomy on rooting depth was observed for the thinner root classes. We found no evidence that root thickening is related to deeper rooting in compacted soil; however, anatomical traits are important, especially for thinner root classes
Thinking beyond the hybrid:“actually-existing” cities “after neoliberalism” in Boyle <i>et al.</i>
In their article, ‘The spatialities of actually existing neoliberalism in Glasgow, 1977 to present’, Mark Boyle, Christopher McWilliams and Gareth Rice (2008) usefully problematise our current understanding of neoliberal urbanism. Our response is aimed at developing a sympathetic but critical approach to Boyle et al's understanding of neoliberal urbanism as illustrated by the Glasgow example. In particular, the counterposing by Boyle et al of a 'hybrid, mutant' model to a 'pure' model of neoliberalism for us misrepresents existing models of neoliberalism as a perfectly finished object rather than a roughly mottled process. That they do not identify any ‘pure’ model leads them to create a straw construct against which they can claim a more sophisticated, refined approach to the messiness of neoliberal urbanism. In contrast, we view neoliberalism as a contested and unstable response to accumulation crises at various scales of analysis
An Empirical Examination of Two Models of Cultural Causation
The traditional macroscopic model of cultural causation advanced by Weber and modified by Parsons assumes that values provide orientation for human action. Thus, values are conceptualized as the intervening link between culture and behavior and in general, are viewed as predictive of human action. Swidler (1986) contends that values are a poor predictor of behavior. As an a/tentative model, Swidler asserts that cultures provide actors with a limited array of behavioral options. Because this array is finite and indicative of a particular cultural setting, inuacultural behavioral similatities are observable. We empirically test the link between culture and behavior in a situation which Swidler defines as "unsettled lives." Our findings offer little support for the traditionally assumed link between values and behavior. The theoretical implications of our findings are discussed and an expansion of Swidler's model is offered
A quantitative study of neurochemically-defined populations of inhibitory interneurons in the superficial dorsal horn of the mouse spinal cord
Around a quarter of neurons in laminae I-II of the dorsal horn are inhibitory interneurons. These play an important role in modulating somatosensory information, including that perceived as pain or itch. Previous studies in rat identified four largely non-overlapping neurochemical populations among these cells, defined by expression of galanin, neuropeptide Y (NPY), neuronal nitric oxide synthase (nNOS) or parvalbumin. The galanin cells were subsequently shown to coexpress dynorphin. Several recent studies have used genetically-modified mice to investigate the function of different interneuron populations, and it is therefore important to determine whether the same pattern applies in mouse, and to estimate the relative sizes of these populations. We show that the neurochemical organisation of inhibitory interneurons in mouse superficial dorsal horn is similar to that in the rat, although a larger proportion of these neurons (33%) express NPY. Between them, these four populations account for ∼75% of inhibitory cells in laminae I-II. Since ∼25% of inhibitory interneurons in this region belong to a novel calretinin-expressing type, our results suggest that virtually all inhibitory interneurons in superficial dorsal horn can be assigned to one of these five neurochemical populations. Although our main focus was inhibitory neurons, we also identified a population of excitatory dynorphin-expressing cells in laminae I-II that are largely restricted to the medial part of the mid-lumbar dorsal horn, corresponding to glabrous skin territory. These findings are important for interpretation of studies using molecular-genetic techniques to manipulate the functions of interneuron populations to investigate their roles in somatosensory processing
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