Is there a close association between "soils" and "vegetation"? : A case study from central western New South Wales

The assumption that ‘soils’ and ‘vegetation’ are closely associated was tested by describing soils and vegetation along a Travelling Stock Reserve west of Grenfell, New South Wales (lat 33° 55’S, long 147° 45’E). The transect was selected on the basis of (a) minimising the effects of non-soil factors (human interference, climate and relief) on vegetation and (b) the presence of various soil and vegetation types as indicated by previous mapping. ‘Soils’ were considered at three levels: soil landscapes (a broad mapping unit widely used in central western NSW), soil types (according to a range of classifications) and soil properties (depth, pH, etc.). ‘Vegetation’ was considered in three ways: vegetation type (in various classifications), density/floristic indices (density of woody species, abundance of native species, etc.) and presence/absence of individual species. Sites along the transect were grouped according to soil landscapes or soil types and compared to vegetation types or indices recorded at the sites. Various measures indicated low associations between vegetation types and soil landscapes or soil types. Except for infrequent occurrences of a soil type or landscape, any one soil type or landscape was commonly associated with a number of vegetation types and any one vegetation type was associated with a number of soil landscapes or soil types. However, significant associations between some vegetation indices, mainly density or numbers of woody species, and some soil landscapes and soil types were evident. Although many species were relatively ubiquitous, some groups of species that were restricted to one or two soil types were identified. Canonical Correspondence Analysis provided some suggestions as to which properties (e.g. texture) of these soils were associated with the presence of particular species

Four rural cemeteries in central western NSW: Islands of Australiana in a European sea?

Vascular plants present in groundstoreys of variously–managed areas in four cemeteries in central western NSW – two on the Central Western Slopes (Garra and Toogong) and two on the Central Tablelands (Lyndhurst and Carcoar) – were recorded over periods of 6–10 years. It was hypothesised that (a) areas of the cemeteries with a history of nil or low disturbance would represent high quality remnant vegetation (i.e. contain a diversity of native species but few naturalised species), and (b) that clearing of woody vegetation, together with similar management (e.g. regular mowing) would result in homogenisation of the groundstoreys such that many species, native and naturalised, would be common to all sites. 344 species (176 native, 154 naturalised and 14 non–naturalised exotics) were recorded across the four cemeteries. Many native species that were rare in the surrounding agricultural lands were present in the cemeteries (enhancing their value as conservation areas) but no cemetery contained areas of groundstorey that would qualify as ‘pristine’. Across all management areas, the proportions of naturalised species in the native + naturalised floras of the cemeteries ranged from 46 to 55 %. Though never dominant, naturalised species also comprised high proportions (42 to 51 %) of the floras of the least disturbed (nil or infrequently mown) areas within each cemetery. Many (40 %) of the species recorded occurred at only one cemetery. This partly explained why the floras of similarly– managed parts of cemeteries on the Central Western Slopes were, contrary to expectations, markedly different to those on the Central Tablelands. However, within the same botanic subdivision, floras – particularly of naturalised species in regularly mown grasslands – were more similar (‘homogenised’) than those of nil or infrequently mown grasslands

Indeterminacy and instability in Petschek reconnection

We explain two puzzling aspects of Petschek's model for fast reconnection. One is its failure to occur in plasma simulations with uniform resistivity. The other is its inability to provide anything more than an upper limit for the reconnection rate. We have found that previously published analytical solutions based on Petschek's model are structurally unstable if the electrical resistivity is uniform. The structural instability is associated with the presence of an essential singularity at the X-line that is unphysical. By requiring that such a singularity does not exist, we obtain a formula that predicts a specific rate of reconnection. For uniform resistivity, reconnection can only occur at the slow, Sweet-Parker rate. For nonuniform resistivity, reconnection can occur at a much faster rate provided that the resistivity profile is not too flat near the X-line. If this condition is satisfied, then the scale length of the nonuniformity determines the reconnection rate

Axial Multicentric Osteosarcoma in an English Cocker Spaniel

No abstract available

Multimegawatt Nuclear Reactor Design for Plasma Propulsion Systems

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76042/1/AIAA-5456-353.pd

Evidence for quantum confinement in the photoluminescence of porous Si and SiGe

We have used anodization techniques to process porous surface regions in p-type Czochralski Si and in p-type Si0.85Ge0.15 epitaxial layers grown by molecular beam epitaxy. The SiGe layers were unrelaxed before processing. We have observed strong near-infrared and visible light emission from both systems. Analysis of the radiative and nonradiative recombination processes indicate that the emission is consistent with the decay of excitons localized in structures of one or zero dimensions

Magnetic Gaps related to Spin Glass Order in Fermionic Systems

We provide evidence for spin glass related magnetic gaps in the fermionic density of states below the freezing temperature. Model calculations are presented and proposed to be relevant for explaining resistivity measurements which observe a crossover from variable-range- to activated behavior. The magnetic field dependence of a hardgap and the low temperature decay of the density of states are given. In models with fermion transport a new metal-insulator transition is predicted to occur due to the spin-glass gap, anteceding the spin glass to quantum paramagnet transition at smaller spin density. Important fluctuation effects due to finite range frustrated interactions are estimated and discussed.Comment: 4 pages, 1 Postscript figure, revised version accepted for publication in Physical Review Letter

Renal cortical drug and xenobiotic metabolism following urinary tract obstruction

Renal cortical drug and xenobiotic metabolism following urinary tract obstruction. Renal cortical metabolism of drugs and xenobiotics was assessed with microsomes prepared from normal, contralateral and 4-day postobstructive hydronephrotic kidneys. Microsomal mixed-function oxidase and prostaglandin H synthase systems were determined in control and 3-methylcholanthrene-treated rabbits. Cytochrome P450 content and biphenyl-4-hydroxylase activity but not cytochromec reductase activity were reduced in the hydronephrotic kidney. 3-Methylcholanthrene treatment increased cytochrome P450 content and biphenyl-4-hydroxylase and acetanilide-4-hydroxylase activities in normal, contralateral, and hydronephrotic kidneys. However, even after 3-methylcholanthrene treatment, hydronephrotic kidney cytochrome P450 content and acetanilide-4-hydroxylase activity were not more than 20% of the corresponding normal kidney values. Prostaglandin H synthase metabolism of benzidine was observed in the hydronephrotic kidney but was at the limit of detection in normal or contralateral kidneys with or without 3-methylcholanthrene treatment. Characteristics of benzidine metabolism were consistent with the hydroperoxidase rather than the fatty acid cyclooxygenase activity of prostaglandin H synthase. Therefore, hydronephrosis alters the drug and xenobiotic metabolic profile of the renal cortex from a primarily mixed-function oxidase-dependent system to one with the potential for metabolism by the hydroperoxidase component of prostaglandin H synthase.Métabolisme cortical rénal des médicaments et xénobiotiques après obstruction du tractus urinaire. Le métabolisme cortical rénal de médicaments et de xénobiotiques a été étudié avec des microsomes préparés à partir des reins normaux, controlatérals, et hydronéphrotiques, 4 jours après une obstruction. Les systèmes microsomiaux de fonction oxydase mixte et de prostaglandine H synthétase ont été déterminés chez des lapins contrôles et traités par du 3-méthylcholanthrène. Le contenu en cytochrome P450 et l'activité biphényl-4-hydroxylase, mais non l'activité cytochromec réductase étaient diminués dans le rein hydronéphrotique. Le traitement par le 3-méthylcholanthrène a augmenté le contenu en cytochrome P450 et les activités biphényl-4-hydroxylase et acétanilide-4-hydroxylase chez les reins normaux, controlatérals et hydronéphrotiques. Cependant, même après traitement par le 3-méthylcholanthrène, le contenu en cytochrome P450 du rein hydronéphrotique et son activité acétanilide-4-hydroxylase n'étaient pas de plus de 20% des valeurs dans le rein normaux correspondant. Le métabolisme de la benzidine par la prostaglandine H synthétase était observable dans le rein hydronéphrotique, mais était à la limite de la détection dans les reins normaux ou controlatérals, avec ou sans traitement par le 3-méthylcholanthrène. Les caractéristiques du métabolisme de la benzidine étaient plus compatibles avec l'activité hydroperoxidase qu'avec l'activité cyclooxygénase des acides gras de la prostaglandine H synthétase. Ainsi, l'hydronéphrose altère le profil métabolique des drogues et des xénobiotiques dans le cortex rénal d'un système primitivement dépendant d'une fonction oxydase mixte à un système ayant la capacité de métabolisme par le constituant hydroperoxydase de la prostaglandine H synthétase