Deep weathering of calcareous sedimentary rock and the redistribution of iron and manganese in soil and saprolite

Iron and Mn redistribute in soil and saprolite during weathering. The geological weathering fronts ofcalcareous sedimentary rock were investigated by examining the bulk density, porosity, and distribution ofCa, Fe, and Mn. Core samples were taken ofsoil, saprolite, and bedrock material from both summit (HHMS-4B) and sideslope (HHMS-5A) positions on an interbedded Nolichucky shale and Maryville limestone landform in Solid Waste Storage Area 6 (SWSA-6). This is a low-level radioactive solids waste disposal site on the Dept. ofEnergy (DOE) Oak Ridge Reservation in Roane County Tennessee. This work was initiated because data about the properties of highly weathered sedimentary rock on this site were limited. The core samples were analyzed for pH, calcium carbonate equivalence (CCE), hydroxylamine-extractable (HA) Mn, and dithionite-citrate (CBD)-extractable Fe and Mn. Low pH values occurred from the soil surface down to the depth of the oxidized and leached saprolite in both cores. The CCE and HA-extractable Mn results were also influenced by the weathering that has occurred in these zones. Extractable Mn oxide was higher at a lower depth in the oxidized and leached saprolite compared with the Fe oxide, which was higher in the overlying soil solum. Amounts of Mn oxides were higher in the sideslope core (HHMS-5A) than in the summit core (HHMS-4B). Iron was more abundant in the deeper weathered summit core, but the highest value, 39.4 g kg-1, was found at 1.8 to 2.4 m in the sideslope core. The zone encompassing the oxidized and partially leached saprolite down to the unoxidized and unleached bedrock had higher densities and larger quantities of CaCO3 than the soil solum and oxidized and leached saprolite. The overlying soil and oxidized and leached saprolite had lower pH and CCE values and were higher in Fe and Mn oxides than the oxidized and unleached saprolite. The distribution of Fe and Mn is important when evaluating soil and saprolite for hazardous waste disposal site assessment.

Novel macrocyclic and acyclic cationic lipids for gene transfer: Synthesis and in vitro evaluation

The synthesis and in vitro evaluation of four cationic lipid gene delivery vectors, characterized by acyclic or macrocyclic, and saturated or unsaturated hydrophobic regions, is described. The synthesis employed standard protocols, including ring-closing metathesis for macrocyclic lipid construction. All lipoplexes studied, formulated from plasmid DNA and a liposome composed of a synthesized lipid, 1,2-dimyristoyl-sn-glycero-3-ethylphosphocholine (EPC), and either 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) or cholesterol as co-lipid, exhibited plasmid DNA binding and protection from DNase I degradation, and concentration dependent cytotoxicity using Chinese hamster ovary-K1 cells. The transfection efficiency of formulations with cholesterol outperformed those with DOPE, and in many cases the EPC/cholesterol control, and formulations with a macrocyclic lipid (+/- 10:1) outperformed their acyclic counterparts (+/- 3:1).

Arsenic behaviour from groundwater and soil to crops:impacts on agriculture and food safety

High levels of As in groundwater commonly found in Bangladesh and other parts of Asia not only pose a risk via drinking water consumption but also a risk in agricultural sustainability and food safety. This review attempts to provide an overview of current knowledge and gaps related to the assessment and management of these risks, including the behaviour of As in the soil-plant system, uptake, phytotoxicity, As speciation in foods, dietary habits, and human health risks. Special emphasis has been given to the situation in Bangladesh, where groundwater via shallow tube wells is the most important source of irrigation water in the dry season. Within the soil-plant system, there is a distinct difference in behaviour of As under flooded conditions, where arsenite (AsIII) predominates, and under nonflooded conditions, where arsenate (AsV) predominates. The former is regarded as most toxic to humans and plants. Limited data indicate that As-contaminated irrigation water can result in a slow buildup of As in the topsoil. In some cases the buildup is reflected by the As levels in crops, in others not. It is not yet possible to predict As uptake and toxicity in plants based on soil parameters. It is unknown under what conditions and in what time frame As is building up in the soil. Representative phytotoxicity data necessary to evaluate current and future soil concentrations are not yet available. Although there are no indications that crop production is currently inhibited by As, long-term risks are clearly present. Therefore, with concurrent assessments of the risks, management options to further prevent As accumulation in the topsoil should already have been explored. With regard to human health, data on As speciation in foods in combination with food consumption data are needed to assess dietary exposure, and these data should include spatial and seasonal variability. It is important to control confounding factors in assessing the risks. In a country where malnutrition is prevalent, levels of inorganic As in foods should be balanced against the nutritional value of the foods. Regarding agriculture, As is only one of the many factors that may pose a risk to the sustainability of crop production. Other risk factors such as nutrient depletion and loss of organic matter also must be taken into account to set priorities in terms of research, management, and overall strategy.

Polycyclic aromatic hydrocarbon (PAH) dispersion and deposition to vegetation and soil following a large scale chemical fire

Polycyclic aromatic hydrocarbons (PAHs) were determined in soil and vegetation following a large scale chemical fire involving 10,000 ton of polypropylene. In comparison with sites outside the plume from the fire, PAH concentrations were elevated in grass shoots (by up to 70-fold) and in soil (by up to 370-fold). The pattern of PAH dispersion under the plume was dependent on the physical-chemical properties of individual PAHs. The lighter, least hydrophobic PAHs were dispersed into the environment at greater distances than heavier, more hydrophobic PAHs. At the most distant sampling point (4.5 km) under the plume, the low molecular weight PAHs were still considerably elevated in vegetation samples compared to control sites. Dispersion appeared to be regulated by the compounds partitioning between the vapour and particulate phase, with dry particulate deposition occurring closer to the fire source than gaseous deposition. For all PAHs, the fire resulted in greater contamination of soils compared to grasses, with the relative ratio of plant/soil contamination decreasing as hydrophobicity increased.

Photosynthetic pigments in soils from northern Victoria Land (continental Antarctica) as proxies for soil algal community structure and function

Although soil algae are among the main primary producers in most terrestrial ecosystems of continental Antarctica, there are very few quantitative studies on their relative proportion in the main algal groups and on how their distribution is affected by biotic and abiotic factors. Such knowledge is essential for understanding the functioning of Antarctic terrestrial ecosystems. We therefore analyzed biological soil crusts from northern Victoria Land to determine their pH, electrical conductivity (EC) water content (W), total and organic C (TC and TOC) and total N (TN) contents, and the presence and abundance of photosynthetic pigments. In particular, the latter were tested as proxies for biomass and coarse-resolution community structure. Soil samples were collected from five sites with known soil algal communities and the distribution of pigments was shown to reflect differences in the relative proportions of Chlorophyta, Cyanophyta and Bacillariophyta in these sites. Multivariate and univariate models strongly indicated that almost all soil variables (EC, W, TOC and TN) were important environmental correlates of pigment distribution. However, a significant amount of variation is independent of these soil variables and may be ascribed to local variability such as changes in microclimate at varying spatial and temporal scales. There are at least five possible sources of local variation: pigment preservation, temporal variations in water availability, temporal and spatial interactions among environmental and biological components, the local-scale patchiness of organism distribution, and biotic interactions. (C) 2009 Elsevier Ltd. All rights reserved.

Using geostatistical Bayesian Updating to integrate airborne radiometrics and soil geochemistry to improve mapping for mineral exploration

Mineral exploration programmes around the world use data from remote sensing, geophysics and direct sampling. On a regional scale, the combination of airborne geophysics and ground-based geochemical sampling can aid geological mapping and economic minerals exploration. The fact that airborne geophysical and traditional soil-sampling data are generated at different spatial resolutions means that they are not immediately comparable due to their different sampling density. Several geostatistical techniques, including indicator cokriging and collocated cokriging, can be used to integrate different types of data into a geostatistical model. With increasing numbers of variables the inference of the cross-covariance model required for cokriging can be demanding in terms of effort and computational time. In this paper a Gaussian-based Bayesian updating approach is applied to integrate airborne radiometric data and ground-sampled geochemical soil data to maximise information generated from the soil survey, to enable more accurate geological interpretation for the exploration and development of natural resources. The Bayesian updating technique decomposes the collocated estimate into a production of two models: prior and likelihood models. The prior model is built from primary information and the likelihood model is built from secondary information. The prior model is then updated with the likelihood model to build the final model. The approach allows multiple secondary variables to be simultaneously integrated into the mapping of the primary variable. The Bayesian updating approach is demonstrated using a case study from Northern Ireland where the history of mineral prospecting for precious and base metals dates from the 18th century. Vein-hosted, strata-bound and volcanogenic occurrences of mineralisation are found. The geostatistical technique was used to improve the resolution of soil geochemistry, collected one sample per 2 km2, by integrating more closely measured airborne geophysical data from the GSNI Tellus Survey, measured over a footprint of 65 x 200 m. The directly measured geochemistry data were considered as primary data in the Bayesian approach and the airborne radiometric data were used as secondary data. The approach produced more detailed updated maps and in particular maximized information on mapped estimates of zinc, copper and lead. Greater delineation of an elongated northwest/southeast trending zone in the updated maps strengthened the potential to investigate stratabound base metal deposits.

Diversity and abundance of soil arthropods in urban and suburban holm oak stands

We investigated the soil arthropod communities of urban and suburban holm oak (Quercus ilex L.) stands in a small (Siena) and a large Italian city (Naples) and tested whether the abundance and diversity of higher arthropod taxa are affected by the biotic and abiotic conditions of urban forest soils, including pollution. Acarina and Collembola were the dominant taxa in both cities. In Siena the total number of arthropod individuals collected in the samples was over 1/3 greater than in Naples, but all diversity indices scored higher in Naples than in Siena, probably in response to the higher heterogeneity of microclimatic and pedological conditions found in Naples study area. Oribatids resulted twice more abundant in Siena and so were the total mites with respect to Collembola. While “taxonomic richness” per site increased with distance from road traffic, entropy and evenness indices scored higher at the two ends of the impact gradient in both cities. The overall variation in basic pedological and microbiological soil parameters positively correlated with the total abundance of arthropods, and negatively correlated with their taxonomic richness. At the resolution employed, no significant relation emerged between anthropogenic factors, such as traffic load and soil pollution, and the arthropod fauna density and variety. These results are consistent with conclusions drawn from a previous study on the enchytraeid fauna examined at species level, which is remarkable considering the different taxonomic resolutions of the two studies. CCA results suggest that the higher abundance of Oribatid mites, Protura and Thysanura and the lower abundance of Diplopoda and Symphyla in Siena could depend on a higher fungi/bacteria ratio. This observation can be interpreted in terms of differences in fungi and bacteria between the two cities: Siena is shifted towards the fungal decomposition channel, which supports taxa such as oribatid mites, while Naples is shifted towards the bacterial channel, which supports chiefly detritivorous groups, such as diplopods.

Levels of Arsenic and Other Trace Elements in Southern Libyan Agricultural Irrigated Soil and Non-irrigated Soil Projects

The levels of As and various other trace elements found in the irrigated agricultural soil (Tsoil) of southern Libya were compared with non-irrigated soil (Csoil) from the same sampling campaign collected between April and May 2008. The soil samples represented agronomic practice in the southern Libyan regions of Maknwessa (MAK), Aril (ARL) and Taswaa (TAS), and were analyzed by Inductively coupled plasma mass spectrometry (ICP-MS) for Co, Ni, Cu, Se, Mo, Zn, As, Pb, Cd and P. Concentrations of P and As in TAS and MAK were found to be higher in Tsoil compared to Csoil, while the opposite was true for ARL. In general, As concentrations in these areas were 2-3 times lower than the global average. In ARL, the average P concentrations of the Csoil samples were significantly higher than those of Tsoil samples: this site is composed mainly of pasture for animal production, where phosphate fertilizers are used regularly. Distance from the source of irrigation was found to be of an important influence on the heavy metal concentration of the soil, with greater concentrations found closer to the irrigation source. It can be concluded from the results that irrigation water contains elevated levels of As, which finds its way into the soil profile and can lead to accumulation of As in the soil over time.

The fate of 14C-naphthalene in soil microcosms containing Scots pine seedlings and enchytraeids

The fate of freshly spiked and aged ¹⁴C-naphthalene associated residues as investigated in the presence and absence of ectomycorrhizal Scots pine seedlings and enchytraeid worms, in a factorial experimental design. Microcosms were used which enabled the ¹⁴C-labelled naphthalene associated residues to be quantified, including plant lipids which acted as an additional naphthalene sink within the microcosms. The presence of plant roots altered the availability of the ¹⁴C-naphthalene and associated residues to degrading microbes. Mineralisation and volatilisation of ¹⁴C naphthalene in freshly spiked soil were lower in the presence of Scots pine. Conversely, in soil aged for 180 d, Scots pine increased mineralisation, and bioavailability of naphthalene. Root-mediated processes, microbial activity and enchytraeids interact with desorption, bioavailability and mineralisation of naphthalene. © 2006 Elsevier Ltd. All rights reserved.

Volumetric Carbon Content Calculations: A Geostatistical and Compositional Approach

This study applies spatial statistical techniques including cokriging to integrate airborne geophysical (radiometric) data with ground-based measurements of peat depth and soil organic carbon (SOC) to monitor change in peat cover for carbon stock calculations. The research is part of the EU funded Tellus Border project and is supported by the INTERREG IVA development programme of the European Regional Development Fund, which is managed by the Special EU Programmes Body (SEUPB). The premise is that saturated peat attenuates the radiometric signal from underlying soils and rocks. Contemporaneous ground-based measurements were collected to corroborate mapped estimates and develop a statistical model for volumetric carbon content (VCC) to 0.5 metres. Field measurements included ground penetrating radar, gamma ray spectrometry and a soil sampling methodology which measured bulk density and soil moisture to determine VCC. One aim of the study was to explore whether airborne radiometric survey data can be used to establish VCC across a region. To account for the footprint of airborne radiometric data, five cores were obtained at each soil sampling location: one at the centre of the ground radiometric equivalent sample location and one at each of the four corners 20 metres apart. This soil sampling strategy replicated the methodology deployed for the Tellus Border geochemistry survey. Two key issues will be discussed from this work. The first addresses the integration of different sampling supports for airborne and ground measured data and the second discusses the compositional nature of the VOC data.

POPULATION DYNAMICS OF PLANT PARASITIC NEMATODES AND THEIR RELATIONSHIPS WITH SOIL PHYSICO-CHEMICAL PARAMETERS DURING THE FALLOW PERIOD AFTER SUGARBEET AND LEADING INTO TOMATO CULTIVATION

The main objective of this research was the study of the soil nematode community, and in particular plant parasitic nematodes (PPN), from a field located in Portugal’s southern region, used for sugarbeet production. The study was performed from February to July 2003, covering part of the fallow period previous to tomato cultivation, the alternative crop in the rotation. The end of the fallow period in March and the soil preparation period in May were marked by a significant reduction in the numbers of PPN, whereas their numbers increased on the following tomato crop. The genus Helicotylenchus stood out as the most representative group, forming 90% of all PPN counted each month. The genus Heterodera was relatively abundant in the months following the previous sugarbeet crop, and numbers of the genus Meloidogyne increased during the tomato crop. The correlations between these group and environmental parameters show that, apart from the direct influence of the host, pH, organic matter, temperature and soil moisture significantly influenced nematode abundance and community composition.

Soil function and biodiversity: regional variations and climate changes

Embora o objetivo principal da proteção internacional dos solos seja proteger tanto as funções quanto a estrutura do solo, a atual abordagem trata principalmente da proteção ao nível estrutural. Há uma carência de estudos que contemplem a ligação das funções do solo com os níveis da comunidade. Além disso, é ainda desconhecido se as variáveis ambientais (ex: tipos de solo, condições climáticas) atuam nas funções do solo da mesma maneira que influenciam sua estrutura biológica. Ademais, as alterações climáticas poderão ter sozinhas ou combinadas com os poluentes, um grande efeito nos ecossistemas terrestres. O presente trabalho propõe estudar as funções e a estrutura biológica do solo quando impactados devido a estresse tóxico (poluição por Cu) e/ou alterações a fatores como a temperatura e abundância de organismos, de maneira a simular possíveis variações regionais ou climáticas. Para alcançar os objetivos principais 3 experiências utilizando diferentes densidades de E. crypticus e 2 gerações foram feitas (Capítulos II e III). Duas experiências com mesocosmos (SMS) decorreram durante 3 meses sob uma gama de diversas temperaturas (10 – 29°C), que representam temperaturas médias para Portugal e Dinamarca (Capítulos IV e V). Duas experiências de campo também foram realizadas com intuito de validar os SMSs (Capítulo VI). Resultados demonstraram que os efeitos do Cu na reprodução dos enquitraídeos dependem da densidade inicial de organismos, especialmente na 2ª geração. Entretanto, nos SMSs expostos a Cu, a densidade inicial é menos importante nos resultados finais. O aumento da temperatura alterou majoritariamente a fase inicial de crescimento populacional. Em períodos mais longos, a abundância estabilizou tornando-se menos influenciada pelas temperaturas. Períodos longos de exposição reforçaram os efeitos da temperatura, como por ex: diversas espécies foram similarmente afetadas a 29 ou 26°C quando expostas durante 28 ou 61 dias respectivamente. De forma geral, o Cu reduziu a abundância da maioria das espécies ao longo do tempo, com poucas exceções. Os resultados da decomposição da matéria orgânica (MO) e atividade alimentar associaram-se com a abundância de organismos em baixas temperaturas (10-23°C). Entretanto, com o aumento das temperaturas (19-29°C), este comportamento não foi claro e a abundância de espécies e atividade alimentar diminuíram enquanto a decomposição da MO aumentou. Além disso, os resultados observados nos SMSs foram confirmados no campo. Mais especificamente, alterações ocorreram na fase de crescimento (correspondente à Primavera) e a exposição ao Cu diminuiu os efeitos da temperatura. Metodologias mais complexas (ex: mais gerações e experiências com múltiplas espécies) apresentam muitos benefícios, mas também proporcionam respostas mais complexas, as quais exigem um maior “peso” de evidências para serem comprovadas.

Assessing the combined effect of land management and wildfire on runoff and soil erosion in north central Portugal

Strong and sometimes extreme responses in runoff and soil erosion following wildfires have been reported worldwide. However, in the case of North-Central Portugal, little research had been carried out regarding the hydrologic and erosive impacts of several land management activities in recently burnt areas (such as ground preparation, post-fire logging or post-fire mitigation treatments). This study aims to assess post-fire runoff and soil erosion response on Eucalypt and Maritime pine plantations during the first, second and third years following wildfires. The effect of several pre-fire ground preparation operations (ploughed down-slope, contour ploughed and inclined terraces), post-fire logging activities (on both the eucalypt and pine plantations), as well as the application of hydromulch (a post-fire emergency treatment) on overland flow and soil erosion were compared to burnt but undisturbed and untreated areas. The intensive monitoring of runoff, soil erosion and selected soil properties served to determine the main factors involved in post-fire runoff and soil erosion and their spatial and temporal variation. Soil water repellency deserved special attention, due to its supposed important role for overland flow generation. Repeated rainfall simulation experiments (RSE’s), micro-scale runoff plots and bounded sediment fences were carried out and/or installed immediately after the wildfire on seven burnt slopes. Micro-scale runoff plots results under natural rainfall conditions were also compared to the RSE’s results, which was useful for assessing the representativeness of the data obtained with artificial rainfall. The results showed comparable runoff coefficient (20-60%) but lower sediment losses (125-1000 g m-2) than prior studies in Portugal, but especially outside Portugal. Lower sediment losses were related with the historic intensive land use in the area. In evaluating these losses, however, the shallowness and stoniness of the soils, as well as the high organic matter fraction of the eroded sediments (50%) must not be overlooked. Sediment limited erosion was measured in all the ploughed sites, probably due to the time since ploughing (several years). The disturbance of the soil surface cover due to post-fire logging and wood extraction substantially increased sediment losses at both the pine and eucalypt sites. Hydromulch effectiveness in reducing the runoff (70%) and sediment losses (83%) was attributed to the protective high coverage provided by hydromulch. The hydromulch significantly affected the soil cover and other soil properties and these changes also reduced the soil erosion risk. The rainfall amount was the main factor explaining the variance in runoff. However, a shift from rainfall amount to rainfall intensity was detected when either the surface cover or the infiltration capacity (hydrophilic conditions) increased. Sediment losses were controlled by rainfall intensity and surface cover. The role of soil water repellency on runoff generation was not consistent; the overall repellency levels alone were not enough to assess its hydrological impact. Soil water repellency explained runoff generation in the specific-sites model better than in the overall model. Additionally, soil moisture content was a better predictor for soil water repellency than antecedent rainfall. The natural rainfall results confirmed that RSE’s were able to capture the specific sediment losses and its organic matter content as well as the differences between the ploughed and unploughed sites. Repeated RSE’s also captured the seasonal variations in runoff and sediment losses attributed to soil water repellency. These results have implications for post-fire soil erosion modelling and soil conservation practices in the region, or areas with the same land use, climate and soil characteristics. The measured sediment loss, as well as the increasing frequency of ploughing in recently burnt and unburnt eucalypt stands, suggests ploughing is not an effective as a soil conservation measure. Logging activities with less impact are recommended in order to maintain the forest litter protecting the soil surface. Due to its high effectiveness in reducing runoff and soil erosion, hydromulch is recommended for highly sensitive and vulnerable areas.

Understanding and modelling hydrological and soil erosion processes in burnt forest catchments

Forest fires implications in overland flow and soil erosion have been researched for several years. Therefore, is widely known that fires enhance hydrological and geomorphological activity worldwide as also in Mediterranean areas. Soil burn severity has been widely used to describe the impacts of fire on soils, and has being recognized as a decisive factor controlling post-fire erosion rates. However, there is no unique definition of the term and the relationship between soil burn severity and post-fire hydrological and erosion response has not yet been fully established. Few studies have assessed post-fire erosion over multiple years, and the authors are aware of none which assess runoff. Small amount of studies concerning pre-fire management practices were also found. In the case of soil erosion models, the Revised Universal Soil Loss Equation (RUSLE) and the revised Morgan–Morgan–Finney (MMF) are well-known models, but not much information is available as regards their suitability in predicting post-fire soil erosion in forest soils. The lack of information is even more pronounced as regards post-fire rehabilitation treatments. The aim of the thesis was to perform an extensive research under the post fire hydrologic and erosive response subject. By understanding the effect of burn severity in ecosystems and its implications regarding post fire hydrological and erosive responses worldwide. Test the effect of different pre-fire land management practices (unplowed, downslope plowed and contour plowed) and time-since-fire, in the post fire hydrological and erosive response, between the two most common land uses in Portugal (pine and eucalypt). Assess the performance of two widely-known erosion models (RUSLE and Revised MMF), to predict soil erosion rates during first year following two wildfires of distinctive burn severity. Furthermore, to apply these two models considering different post-fire rehabilitation treatments in an area severely affected by fire. Improve model estimations of post-fire runoff and erosion rates in two different land uses (pine and eucalypt) using the revised MMF. To assess these improvements by comparing estimations and measurements of runoff and erosion, in two recently burned sites, as also with their post fire rehabilitation treatments. Model modifications involved: (1) focusing on intra-annual changes in parameters to incorporate seasonal differences in runoff and erosion; and (2) inclusion of soil water repellency in runoff predictions. Additionally, validate these improvements with the application of the model to other pine and eucalypt sites in Central Portugal. The review and meta-analysis showed that fire occurrence had a significant effect on the hydrological and erosive response. However, this effect was only significantly higher with increasing soil burn severity for inter-rill erosion, and not for runoff. This study furthermore highlighted the incoherencies between existing burn severity classifications, and proposed an unambiguous classification. In the case of the erosion plots with natural rainfall, land use factor affected annual runoff while land management affected both annual runoff and erosion amounts significantly. Time-since-fire had an important effect in erosion amounts among unplowed sites, while for eucalypt sites time affected both annual runoff and erosion amounts. At all studied sites runoff coefficients increase over the four years of monitoring. In the other hand, sediment concentration in the runoff, recorded a decrease during the same period. Reasons for divergence from the classic post-fire recovery model were also explored. Short fire recurrence intervals and forest management practices are viewed as the main reasons for the observed severe and continuing soil degradation. The revised MMF model presented reasonable accuracy in the predictions while the RUSLE clearly overestimated the observed erosion rates. After improvements: the revised model was able to predict first-year post-fire plot-scale runoff and erosion rates for both forest types, these predictions were improved both by the seasonal changes in the model parameters; and by considering the effect of soil water repellency on the runoff, individual seasonal predictions were considered accurate, and the inclusion of the soil water repellency in the model also improved the model at this base. The revised MMF model proved capable of providing a simple set of criteria for management decisions about runoff and erosion mitigation measures in burned areas. The erosion predictions at the validation sites attested both to the robustness of the model and of the calibration parameters, suggesting a potential wider application.