Groundwater-induced accumulation of iron oxides and phosphorus retention in severely leached soils

2004 ◽  
Vol 55 (2) ◽  
pp. 213 ◽  
Author(s):  
Song Qiu ◽  
Arthur McComb
Keyword(s):  
Coastal Plain ◽  
Sandy Soils ◽  
Phosphorus Retention ◽  
X Ray ◽  
Fe Oxides ◽  
Swan Coastal Plain ◽  
Groundwater Irrigation ◽  
Soil Salinisation ◽  
Novel Concept ◽  
P Retention

Many sandy soils of the Swan Coastal Plain, Western Australia, are poor in Fe and P retention. A novel concept proposes to relocate Fe from groundwater to surface soils via watering, which should consequently improve P retention. To test the viability of this concept we examined several soils in Perth suburbs that had been watered for 3–27 years with groundwater containing high Fe. Energy dispersive X-ray microanalysis indicated that ‘Fe-watered’ soils had significantly higher Fe materials on the surface of soil particles. Oxalate-extractable Fe (Feo) increased by 52 times and citrate/dithionite-extractable Fe (Fed) increased by 6.6 times. Unusually high Feo/d ratios (average Feo/d = 0.71) in ‘Fe-watered’ soils strongly suggest that the accumulated Fe materials are predominantly amorphous and secondary Fe oxides, probably ferrihydrite. There was a substantial increase in P retention in top-soils, to a magnitude of 45–128 times, demonstrating that increasing Fe oxides in severely leached soils, caused by groundwater irrigation, increases P retention. This approach could be applied to other areas with similar physical characteristics and the present study demonstrates that watering with Fe rich groundwater might have strategic significance not only in the control of water pollution, but also in the rational use of water resources and the amelioration of soil salinisation associated with rising watertables.

Radiological consequences of amending soils with bauxite residue gypsum mixtures

Soil Research ◽  
1993 ◽  
Vol 31 (4) ◽  
pp. 533 ◽  
Author(s):  
KJ Summers ◽  
BH O'Connor ◽  
DR Fox
Keyword(s):  
Coastal Plain ◽  
Soil Amendment ◽  
Radiation Flux ◽  
Bauxite Residue ◽  
Sandy Soils ◽  
Linear Increase ◽  
Swan Coastal Plain ◽  
South West ◽  
Application Rates ◽  
Incremental Dose

This paper reports on the gamma (�) radiation flux from sandy soils of the Swan Coastal Plain treated with bauxite residue/gypsum at various application rates and assesses the radiological significance of soil amendment in relation to currently accepted standards. Amendment rates of up to 2000 t ha-1 of bauxite residue were used. There is a linear increase of incremental � dose with increasing rate of residue. The 1 mSv limit for incremental � dose exposure for the general public is reached for 100% occupancy at an amendment rate of 1500 t ha-1 of bauxite residue. The gamma rate of approximately 0.15 �Gy h-1 is similar to that for soils of much of the area between Bunbury and Capel in the south-west of Western Australia and is significantly lower than levels for Minninup beach where there are deposits of mineral sands.

scholarly journals Objective Evaluation of Deep Uncertainty Predictions for COVID-19 Detection

2021 ◽  
Author(s):  
Hamzeh Asgharnezhad ◽  
Afshar Shamsi ◽  
Roohallah Alizadehsani ◽  
Abbas Khosravi ◽  
Saeid Nahavandi ◽  
...  
Keyword(s):  
Uncertainty Quantification ◽  
Performance Metrics ◽  
Confusion Matrix ◽  
Objective Evaluation ◽  
X Rays ◽  
The Novel ◽  
X Ray ◽  
Uncertainty Estimates ◽  
Chest X Ray ◽  
Novel Concept

Abstract Deep neural networks (DNNs) have been widely applied for detecting COVID-19 in medical images. Existing studies mainly apply transfer learning and other data representation strategies to generate accurate point estimates. The generalization power of these networks is always questionable due to being developed using small datasets and failing to report their predictive confidence. Quantifying uncertainties associated with DNN predictions is a prerequisite for their trusted deployment in medical settings. Here we apply and evaluate three uncertainty quantification techniques for COVID-19 detection using chest X-Ray (CXR) images. The novel concept of uncertainty confusion matrix is proposed and new performance metrics for the objective evaluation of uncertainty estimates are introduced. Through comprehensive experiments, it is shown that networks pertained on CXR images outperform networks pretrained on natural image datasets such as ImageNet. Qualitatively and quantitatively evaluations also reveal that the predictive uncertainty estimates are statistically higher for erroneous predictions than correct predictions. Accordingly, uncertainty quantification methods are capable of flagging risky predictions with high uncertainty estimates. We also observe that ensemble methods more reliably capture uncertainties during the inference. DNN-based solutions for COVID-19 detection have been mainly proposed without any principled mechanism for risk mitigation. Previous studies have mainly focused on on generating single-valued predictions using pretrained DNNs. In this paper, we comprehensively apply and comparatively evaluate three uncertainty quantification techniques for COVID-19 detection using chest X-Ray images. The novel concept of uncertainty confusion matrix is proposed and new performance metrics for the objective evaluation of uncertainty estimates are introduced for the first time. Using these new uncertainty performance metrics, we quantitatively demonstrate where and when we could trust DNN predictions for COVID-19 detection from chest X-rays. It is important to note the proposed novel uncertainty evaluation metrics are generic and could be applied for evaluation of probabilistic forecasts in all classification problems.

A revision of the textricellin spider genus Raveniella (Araneae:Araneoidea:Micropholcommatidae): exploring patterns of phylogeny and biogeography in an Australian biodiversity hotspot

2010 ◽  
Vol 24 (3) ◽  
pp. 209 ◽  
Author(s):  
Michael G. Rix ◽  
Mark S. Harvey ◽  
J. Dale Roberts
Keyword(s):  
New Species ◽  
Western Australia ◽  
Coastal Plain ◽  
Mitochondrial Protein ◽  
Biodiversity Hotspot ◽  
Rrna Genes ◽  
Protein Coding ◽  
Swan Coastal Plain ◽  
Coastal Species ◽  
Eastern Australia

South-western Western Australia is a biodiversity hotspot, with high levels of local endemism and a rich but largely undescribed terrestrial invertebrate fauna. Very few phylogeographic studies have been undertaken on south-western Australian invertebrate taxa, and almost nothing is known about historical biogeographic or cladogenic processes, particularly on the relatively young, speciose Quaternary sand dune habitats of the Swan Coastal Plain. Phylogeographic and taxonomic patterns were studied in textricellin micropholcommatid spiders belonging to the genus Raveniella Rix & Harvey. The Micropholcommatidae is a family of small spiders with a widespread distribution in southern Western Australia, and most species are spatially restricted to refugial microhabitats. In total, 340 specimens of Raveniella were collected from 36 surveyed localities on the Swan Coastal Plain and 17 non-Swan Coastal Plain reference localities in south-western Western Australia. Fragments from three nuclear rRNA genes (5.8S, 18S and ITS2), and one mitochondrial protein-coding gene (COI) were used to infer the phylogeny of the genus Raveniella, and to examine phylogeographic patterns on the Swan Coastal Plain. Five new species of Raveniella are described from Western Australia (R. arenacea, sp. nov., R. cirrata, sp. nov., R. janineae, sp. nov., R. mucronata, sp. nov. and R. subcirrata, sp. nov.), along with a single new species from south-eastern Australia (R. apopsis, sp. nov.). Four species of Raveniella were found on the Swan Coastal Plain: two with broader distributions in the High Rainfall and Transitional Rainfall Zones (R. peckorum Rix & Harvey, R. cirrata); and two endemic to the Swan Coastal Plain, found only on the western-most Quindalup dunes (R. arenacea, R. subcirrata). Two coastally restricted species (R. subcirrata, R. janineae) were found to be morphologically cryptic but genetically highly distinct, with female specimens morphologically indistinguishable from their respective sister-taxa (R. cirrata and R. peckorum). The greater Perth region is an important biogeographic overlap zone for all four Swan Coastal Plain species, where the ranges of two endemic coastal species join the northern and south-western limits of the ranges of R. peckorum and R. cirrata, respectively. Most species of Raveniella were found to occupy long, highly autapomorphic molecular branches exhibiting little intraspecific variation, and an analysis of ITS2 rRNA secondary structures among different species of Raveniella revealed the presence of an extraordinary hypervariable helix, ranging from 31 to over 400 nucleotides in length.

Environmental monitoring of acid sulphate soils in the Swan Coastal Plain, using hyperspectral methods

2006 ◽  
Vol 2006 (1) ◽  
pp. 1-4
Author(s):  
I. C. Lau ◽  
T. J. Cudahy ◽  
C.C.H. Ong ◽  
R.J.J. Vogwill ◽  
S. L. McHugh ◽  
...  
Keyword(s):  
Environmental Monitoring ◽  
Coastal Plain ◽  
Acid Sulphate ◽  
Acid Sulphate Soils ◽  
Swan Coastal Plain
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