scholarly journals Exploring the sensitivity on a soil area-slope-grading relationship to changes in process parameters using a pedogenesis model

2016 ◽  
Vol 4 (3) ◽  
pp. 607-625 ◽  
Author(s):  
W. D. Dimuth P. Welivitiya ◽  
Garry R. Willgoose ◽  
Greg R. Hancock ◽  
Sagy Cohen
Keyword(s):  
Small Area ◽  
Surface Soil ◽  
Physical Dependence ◽  
Surface Erosion ◽  
Small Areas ◽  
Stress Threshold ◽  
Different Depths ◽  
Self Organisation ◽  
The Relationship ◽  
Bedrock Outcrop

Abstract. This paper generalises the physical dependence of the relationship between contributing area, local slope, and the surface soil grading using a pedogenesis model and allows an exploration of soilscape self-organisation. A parametric study was carried out using different parent materials, erosion, and weathering mechanisms. These simulations confirmed the generality of the area-slope-d50 relationship. The relationship is also true for other statistics of soil grading (e.g. d10,d90) and robust for different depths within the profile. For small area-slope regimes (i.e. hillslopes with small areas and/or slopes) only the smallest particles can be mobilised by erosion and the area-slope-d50 relationship appears to reflect the erosion model and its Shield's Stress threshold. For higher area-slope regimes, total mobilization of the entire soil grading occurs and self-organisation reflects the relative entrainment of different size fractions. Occasionally the interaction between the in-profile weathering and surface erosion draws the bedrock to the surface and forms a bedrock outcrop. The study also shows the influence on different depth-dependent in-profile weathering functions in the formation of the equilibrium soil profile and the grading characteristics of the soil within the profile. We outline the potential of this new model and its ability to numerically explore soil and landscape properties.

scholarly journals Exploring the sensitivity on a soil area-slope-grading relationship to changes in process parameters using a pedogenesis model

2016 ◽  
Author(s):  
W. D. D. P. Welivitiya ◽  
Garry R. Willgoose ◽  
Greg R. Hancock ◽  
Sagy Cohen
Keyword(s):  
Small Area ◽  
Surface Soil ◽  
Physical Dependence ◽  
Surface Erosion ◽  
Small Areas ◽  
Stress Threshold ◽  
Different Depths ◽  
Self Organisation ◽  
The Relationship ◽  
Bedrock Outcrop

Abstract. This paper generalises the physical dependence of the relationship between contributing area, local slope, and the surface soil grading first described by Cohen et al, [2009, 2010] using their mARM1D and mARM3D pedogenesis models. A more general computational model, SSSPAM5D, extending the conceptualisation of mARM3D has been developed to further our exploration of soilscape self-organisation. A parametric study was carried out using different parent materials, erosion, and weathering mechanisms. These simulations confirmed the generality of the area-slope-d50 relationship. The relationship is also true for other statistics of soil grading (e.g. d10, d90) and robust for different depths within the profile. For small area-slope regimes (i.e. hillslopes with small areas and/or slopes) only the smallest particles can be mobilised by erosion and the area-slope-d50 relationship appears to reflect the erosion model and its Shields Stress threshold. For higher area-slope regimes, total mobilization of the entire soil grading occurs and self-organisation reflects the relative entrainment of different size fractions. Occasionally the interaction between the in-profile weathering and surface erosion draws the bedrock to the surface and forms a bedrock outcrop. The study also shows the influence on different depth dependent in-profile weathering functions in the formation of the equilibrium soil profile and the grading characteristics of the soil within the profile.

Improving the quality of disaggregated SDG indicators with cluster information for small area estimates

2020 ◽  
Vol 36 (4) ◽  
pp. 955-961
Author(s):  
Rizky Zulkarnain ◽  
Dwi Jayanti ◽  
Tri Listianingrum
Keyword(s):  
Small Area ◽  
Research University ◽  
Direct Method ◽  
Random Effect ◽  
Auxiliary Information ◽  
District Level ◽  
Small Areas ◽  
Associate Dean ◽  
Development Goals

The increasing needs for more disaggregated data motivates National Statistical Offices (NSOs) to develop efficient methods for producing official statistics without compromising on quality. In Indonesia, regional autonomy requires that Sustainable Development Goals (SDGs) indicators are available up to the district level. However, several surveys such as the Indonesian Demographic and Health Survey produce estimates up to the provincial level only. This generates gaps in support for district level policies. Small area estimation (SAE) techniques are often considered as alternatives for overcoming this issue. SAE enables more reliable estimation of the small areas by utilizing auxiliary information from other sources. However, the standard SAE approach has limitations in estimating non-sampled areas. This paper introduces an approach to estimating the non-sampled area random effect by utilizing cluster information. This model is demonstrated via the estimation of contraception prevalence rates at district levels in North Sumatera province. The results showed that small area estimates considering cluster information (SAE-cluster) produce more precise estimates than the direct method. The SAE-cluster approach revises the direct estimates upward or downward. This approach has important implications for improving the quality of disaggregated SDGs indicators without increasing cost. The paper was prepared under the kind mentorship of Professor James J. Cochran, Associate Dean for Research, Prof. of Statistics and Operations Research, University of Alabama.

scholarly journals CO observations of the 30-Doradus region using SEST

1991 ◽  
Vol 148 ◽  
pp. 157-159
Author(s):  
R. S. Booth ◽  
L.E.B. Johansson
Keyword(s):  
Molecular Clouds ◽  
Small Areas ◽  
The Relationship ◽  
Co Observations ◽  
30 Doradus

Using the Swedish-ESO Submillimetre Telescope, we have mapped the CO (1-0) emission in two small areas of the LMC near 30 Dor. Some 20 molecular clouds have been identified and analysed. Cloud masses are calculated assuming virial equilibrium and the relationship between mass and CO luminosity is discussed.

scholarly journals Weaving the Common Threads of Simulation and Formation studies in Archaeology

2017 ◽  
Author(s):  
Benjamin Davies
Keyword(s):  
Computer Simulation ◽  
Human Activity ◽  
Computational Models ◽  
Experimental Studies ◽  
Surface Erosion ◽  
Archaeological Record ◽  
The Common ◽  
The Relationship ◽  
Material Record

Computer simulation is a tool increasingly used by archaeologists to build theories about past human activity; however, simulation has had a limited role theorising about the relationship between past behaviours and the formation of observed patterning in the material record. This paper visits the argument for using simulation as a means of addressing the gap that exists between archaeological interpretations of past behaviours and their physical residues. It is argued that simulation is used for much the same reason that archaeologists use ethnographic or experimental studies, and that computational models can help to address some of the practical limitations of these approaches to record formation. A case study from arid Australia, examining the effects of episodic surface erosion on the visibility of the record, shows how simple, generative simulations, grounded in formational logic, can be used to compare different explanatory mechanisms and suggest tests of the archaeological record itself.

Nitrification and Denitrification Potentials of Soil in Liaohe Estuary Wetland

2014 ◽  
Vol 675-677 ◽  
pp. 71-74
Author(s):  
Ying Xiao ◽  
Ji Song Yang
Keyword(s):  
Incubation Period ◽  
Exponential Decay ◽  
Nitrogen Cycle ◽  
Surface Soil ◽  
Significant Difference ◽  
Different Depths ◽  
Nitrification And Denitrification

Nitrification and denitrification plays an important role in the nitrogen cycle in wetlands. The nitrification and denitrification potentials of soil from different depths (0-40 cm) in Liaohe estuary wetland were studied with laboratorial batch incubation for three weeks. The results showed that the percent of nitrification and denitrification in soil at different depth were about 25-40% and 31-63% of soil total added nitrogen over three weeks, respectively. Both the denitrification and nitrification of soil at different depth showed an exponential decay trend over the incubation period. The corresponding rates were 0.013–0.021 mg·kg-1·d-1and 0.017–0.057 mg·kg-1·d-1. The value of surface soil (0-5cm) was significant higher than that of the subsoil (5-40 cm) (p< 0.05) and there was no significant difference between values of the subsoil (p> 0.05).

Ideal for particularly small areas

OPE Journal ◽  
2021 ◽  
Vol 11 (34) ◽  
pp. 30-30
Keyword(s):  
Small Area ◽  
Fill Factor ◽  
Small Areas

Dracula Technologies (Valence, France) has achieved a new fill factor record for an OPV module with fully inkjet-printed layers. These small-area modules target indoor applications

scholarly journals Development of Shallow-Depth Soil Temperature Estimation Model Based on Thermal Response in Permafrost Area

2018 ◽  
Vol 8 (10) ◽  
pp. 1886 ◽  
Author(s):  
Keunbo Park ◽  
Heekwon Yang ◽  
Bang Lee ◽  
Dongwook Kim
Keyword(s):  
Soil Temperature ◽  
Temperature Measurement ◽  
Thermal Response ◽  
Estimation Model ◽  
Temperature Estimation ◽  
Soil Temperatures ◽  
Different Depths ◽  
The Relationship ◽  
Temperature Depth ◽  
Good Agreement

A soil temperature estimation model for increasing depth in a permafrost area in Alaska near the Bering Sea is proposed based on a thermal response concept. Thermal response is a measure of the internal physical heat transfer of soil due to transferred heat into the soil. Soil temperature data at different depths from late spring to the early autumn period at multiple permafrost sites were collected using automatic sensor measurements. From the analysis results, a model was established based on the relationship between the normalized cumulative soil temperatures (CRCST*i,m and CST*ud,m) of two different depths. CST*ud,m is the parameter of the soil temperature measurement at a depth of 5 cm, and CRCST*i,m is the parameter of the soil temperature measured at deeper depths of i cm (i = 10, 15, 20, and 30). Additionally, the fitting parameters of the mathematical models of the CRCST*i,m–CST*ud,m relationship were determined. The measured soil temperature depth profiles at a different site were compared with their predicted soil temperatures using the developed model for the model validation purpose. Consequently, the predicted soil temperatures at different soil depths using the soil temperature measurement of the uppermost depth (5 cm) were in good agreement with the measured results.

The relationship between animal foraging and nutrient patchiness in south-west Australian woodland soils

Soil Research ◽  
2003 ◽  
Vol 41 (4) ◽  
pp. 665 ◽  
Author(s):  
Mark J. Garkaklis ◽  
J. S. Bradley ◽  
R. D. Wooller
Keyword(s):  
Soil Nutrients ◽  
Surface Soil ◽  
Natural Populations ◽  
Water Infiltration ◽  
European Settlement ◽  
South West ◽  
Bettongia Penicillata ◽  
Australian Continent ◽  
The Relationship ◽  
Preferential Water

The woylie (Bettongia penicillata) was once common and abundant over the southern third of the Australian continent. Since European settlement the range of this rat-kangaroo has become reduced by more than 97%, and until the early 1990s, only 3 small natural populations remained, all in south-western Australia. These medium-sized (c. 1 kg) marsupials create a large number of diggings as they forage for the hypogeous fruiting bodies of ectomycorrhizal fungi upon which they feed. The effect of such foraging activity on the availability of plant nutrients in the vicinity of such diggings was evaluated in simulated digging experiments. Available nitrate, ammonium, and sulfur decreased significantly 3 years after diggings were constructed and had filled in, whereas phosphorus, potassium, iron, and organic carbon remained unchanged. The results suggest that preferential water infiltration via woylie diggings leads to a decrease in those soil nutrients that are susceptible to leaching and indicates that digging vertebrates may influence the distribution of surface soil nutrients.

scholarly journals Relationship between Soil Salinization and Groundwater Hydration in Yaoba Oasis, Northwest China

Water ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 175 ◽  
Author(s):  
Guoqing Cui ◽  
Yudong Lu ◽  
Ce Zheng ◽  
Zhiheng Liu ◽  
Jiamei Sai
Keyword(s):  
Water Quality ◽  
Spatial Distribution ◽  
Soil Salinity ◽  
Irrigation Water ◽  
Surface Soil ◽  
Soil Salinization ◽  
Irrigation Water Quality ◽  
Ion Content ◽  
Soil Salt ◽  
The Relationship

Precipitation is scarce and evaporation is intense in desert areas. Groundwater is used as the main water source to develop agriculture in the oases. However, the effects of using groundwater on the ecological environment elicit widespread public concern. This study investigated the relationship between soil salinity and groundwater characteristics in Yaoba Oasis through in situ experiments. The relationship of the mineral content, pH, and main ion content of groundwater with soil salt was quantitatively evaluated through a gray relational analysis. Four main results were obtained. First, the fresh water area with low total dissolved solid (TDS) was usually HCO3− or SO42− type water, and salt water was mostly Cl− and SO42−. The spatial distribution of main ions in groundwater during winter irrigation in November was basically consistent with that during spring irrigation in June. However, the spatial distribution of TDS differed in the two seasons. Second, soil salinization in the study area was severe, and the salinization rate reached 72.7%. In this work, the spatial variability of soil salinization had a relatively large value, and the values in spring were greater than those in autumn. Third, the soil in the irrigated area had a high salt content, and the salt ion content of surface soil was higher than that of subsoil. A piper trilinear diagram revealed that Ca2+ and K+ + Na+ were the main cations. SO42−, Cl−, and HCO3− were the main anions, and salinization soil mainly contained SO42−. Fourth, the changes in soil salt and ion contents in the 0–10 cm soil layer were approximately similar to those of irrigation water quality, both of which showed an increasing trend. The correlation of surface soil salinity with the salinity of groundwater and its chemical components was high. In summary, this study identified the progress of irrigation water quality in soil salinization and provided a scientific basis for improving the oasis ecosystem, maintaining the healthy development of agriculture, managing oasis water resources, and policy development. Our findings can serve as a reference for other, similar oasis research.

Ethnic minority suicide: a small area geographical study in south London

1999 ◽  
Vol 29 (2) ◽  
pp. 429-436 ◽  
Author(s):  
JAN NEELEMAN ◽  
SIMON WESSELY
Keyword(s):  
Risk Factor ◽  
Ethnic Minority ◽  
Small Area ◽  
Suicide Risk ◽  
Protective Factor ◽  
Minority Groups ◽  
Relative Rate ◽  
Suicide Rates ◽  
And Gender ◽  
The Relationship

Background. The relationship between ethnicity and suicide risk is ill-understood. It is unclear whether, and if so, how, the ethnic mix of local areas affects risk in local individuals.Methods. Coroners' records of 329 suicides were used to obtain ethnic (White, Afro-Caribbean, Asian) suicide rates in South London (population 902008) for 1991–3. Geographical variation and associations of ethnic suicide rates with small area (mean population 8274) ethnic densities (proportion of residents of given ethnic groups) and deprivation, were examined with random effects Poisson regression.Results. Adjusted for deprivation, age and gender, suicide rates in wards with larger minority groups were higher among Whites (relative rate (RR) per standard deviation (S.D.) increase in minority density 1·18; 95% CI 1·02–1·37) but lower among minority groups (RR 0·75 (0·59–0·96)) (LR-test for interaction χ2=9·2 (df=1); P=0·003). Similar patterns were also apparent for Afro-Caribbeans and Asians separately. With White suicide rates as baseline, ethnic minority status is a risk factor for suicide in wards with small, but a protective factor in neighbourhoods with large minority populations. The RR of minority versus White suicide declines with a factor (relative RR) 0·67 (0·51–0·87) per S.D. increase in local minority density.Conclusions. Minority suicide rates are higher in areas where minority groups are smaller. This effect is ethnic-specific and not due to confounding by gender, age, deprivation or unbalanced migration. Dependent on address, a suicide risk factor for a White individual may protect an ethnic minority individual and vice versa. This has implications for research and prevention.

Sign in / Sign up

Export Citation Format

Share Document