Topographic position index (TPI) is an algorithm increasingly used to measure topographic slope positions and to automate landform classifications. We applied TPI to a geoarchaeological research ...project in northwestern Belgium but its use led to erroneous landform classifications in this heterogeneous landscape. We asked whether deviation from mean elevation (DEV) was a better method for landform classification than TPI. We found that it enabled more accurate geomorphological assessment when using northwestern Belgium as a case study.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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•We review pedophysical models and parameters for soil dielectric permittivity prediction.•Geometric parameters link soil texture and bulk dielectric permittivity.•We propose ...semi-empirical pedophysical models that do not require calibration data.•Laboratory and field tests of the new models show an accuracy improvement of up to 412% compared to previous models.
Near surface electromagnetic geophysical techniques are proven tools to support soil ecosystem services and soil exploration. Such geophysical techniques provide electromagnetic properties that are useful to characterize the studied soil. The link between relevant soil characteristics and geophysical properties, such as dielectric permittivity (ε), is commonly expressed by pedophysical models. However, some weaknesses remain in their application, such as the requirement of parameters that are difficult to measure or calculate. Therefore, these parameters are frequently fixed, but this oversimplifies the complexity of the investigated soils. Moreover, the validity of ε pedophysical models in the frequency range of operating soil moisture sensors (normally < 100 MHz) remains poorly investigated.
In this study, the accuracy and adaptability of ε pedophysical models at different electromagnetic frequency ranges was tested and improved using newly collected laboratory and field data. Such data was collected on soils over a wide range of textures, physical and chemical properties.
To achieve this, we review the measurement methods and characteristics of ε pedophysical models, soil phases and geometric parameters. Subsequently, we show how geometric parameters can explain the dependance of soil texture on ε by implementing pedotransfer functions. Then, drawing on a broad experimental basis of common soil types in Europe, we develop novel ε pedophysical models at 50 MHz. These models are not only easy to evaluate but also capture most of the soil’s complexity. Additionally, these new ε pedophysical models eliminate the need for calibration data due to the introduction of novel pedotransfer functions based on soil cation exchange capacity. An extensive model test shows an unprecedented decrease in the RMSE of the newly proposed models of up to 412%.
In conclusion, despite it is unlikely to characterize soil structure, bulk density, or temperature at 50 MHz, these updated PPMs are useful for highly accurate water content and ε predictions, in both laboratory and field conditions, without the need for calibration data. As the developed modelling procedures are valid for a wide range of electromagnetic frequencies, these can be applied to soil exploration with TDR and GPR instrumentation.
For reproducibility, all collected soil data are provided, alongside open-source Python code that contains the presented modelling procedures.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Background & Aims
Approximately 5%–10% of the general population respond inadequately to licensed recombinant hepatitis B vaccines. We assessed the immunogenicity and safety of a new HBAI20 vaccine, ...consisting of a new AI20 adjuvant (20‐µg recombinant human IL‐2 attached to 20‐µg aluminium hydroxide) in combination with HBVaxPro®‐10 µg.
Methods
In a double‐blinded, randomised, controlled phase 2 trial, 18‐ to 59‐year‐old healthy non‐responders (titre <10 mIU/ml after three or more doses of hepatitis B vaccine) were assigned (3:1 ratio) to receive either HBAI20 vaccine or HBVaxPro®‐10 µg in a 0, 1 and 2‐month schedule. The primary outcome was seroprotection (titre ≥ 10 mIU/ml) measured 1‐3 months following the third vaccination.
Results
A total of 133 participants were randomised to receive either HBAI20 vaccine (n = 101) or HBVaxPro®‐10 µg (n = 32). In the modified intention‐to‐treat analysis, the seroprotection rate after the third vaccination was 92.0% (80/87) in the HBAI20 group and 79.3% (23/29) in the HBVaxPro®‐10‐µg group, P = .068. Using a generalised linear mixed model to adjust for stratification factors, a higher odds of seroprotection with HBAI20 vaccine was shown (adjusted odds ratio = 3.48, P = .028). Frequency of mild and moderate local adverse events was greater in the HBAI20 group than in the HBVaxPro®‐10 µg. Rates of severe local adverse events and systemic adverse events were low and similar in both groups.
Conclusions
In this group of hepatitis B vaccine non‐responders, the HBAI20 vaccine demonstrated a higher seroprotection rate when adjusting for stratification factors and a similar safety profile compared to the licensed recombinant HBVaxPro®‐10 µg.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
Subsurface investigation in the Belgian intertidal zone is severely complicated due to high heterogeneity and tides. Near-surface geophysical techniques can offer assistance since they allow fast ...surveying and collection of high spatial density data and frequency domain electromagnetic induction (EMI) was chosen for archaeological prospection on the Belgian shore. However, in the intertidal zone the effects of extreme salinity compromise validity of low-induction-number (LIN) approximated EMI data. In this paper, the effects of incursion of seawater on multi-receiver EMI data are investigated by means of survey results, field observations, cone penetration tests and in-situ electrical conductivity measurements. The consequences of LIN approximation breakdown were researched. Reduced depth of investigation of the quadrature-phase (Qu) response and a complex interpretation of the in-phase response were confirmed. Nonetheless, a high signal-to-noise ratio of the Qu response and viable data with regard to shallow subsurface investigation were also evidenced, allowing subsurface investigation in the intertidal zone.
•An electromagnetic induction survey was performed in the intertidal zone.•Qu and Ph responses are researched.•Low-induction-number approximation breakdown and corrections are investigated.•Survey results are compared with ground truths.•Depth of exploration is researched.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The archaeological evaluation of landscapes in the framework of developer-led archaeology is often based on extensive trenching programmes complemented with auger surveys in wetland environments. ...During the archaeological evaluation of a 90 ha polder site in the north-west of Belgium, a mobile multi-receiver electromagnetic induction (EMI) survey was used as a main prospecting technique. The use of a mobile survey allowed to map the entire study area at a very fine resolution (over 25 measurements per m2). Incorporating a multi-receiver EMI instrument enabled measuring the apparent electrical conductivity (ECa) and the apparent magnetic susceptibility (MSa) of four different soil volumes simultaneously at each location. The detailed maps provided insight into the archaeological and geomorphological features of the site. Among the detected structures were a large medieval farmstead, a palaeoriver system and a number of military remains from World War I (WWI). The vertical discrimination potential added insight into the vertical facies changes, which allowed modeling the palaeolandscape and helped determining the depth of detected medieval features. The different MSa measurements gave additional insight into the WWI structures. In this paper, we give an overview of the possibilities of combining multiple ECa measurements for interpreting vertical soil variability together with an example of the added information from simultaneously gathered MSa data. More generally, the diverse potential of multi-receiver EMI survey for geoarchaeological research is demonstrated.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Soil magnetic measurements are used increasingly to estimate the impact of airborne, combustion-related particulate matter (PM) pollution in dense measurement grids. Although many studies have proven ...the potential of topsoil magnetic measurements in environmental monitoring, their application is not straightforward when factors such as parent material or land use have to be accounted for. Often, the influence of land use on the soil magnetic signal is circumvented by targeting forest soils, where deposited magnetic particles are best preserved in the topsoil. However, when large forests are absent, e.g. in densely populated areas or environments with more heterogeneous land use, this approach often impedes reliable and comprehensive spatial sampling. We evaluated if topsoil magnetic pollution mapping across different land use classes, against a homogeneous geological environment of sandy soils, could help increase the spatial reliability of results in regional scale surveys. Although detailed magnetic property analysis and evaluation of trace metal concentrations in soils on arable land, forest and pasture showed the impact of atmospheric pollution, topsoil susceptibility measurements did not allow delineating the magnetic footprint of PM pollution. Land use strongly influenced the distribution of magnetic particles through soil, and the evaluation of anomalous magnetic topsoil enhancement required the integration of downhole susceptibility soundings. We conclude that topsoil susceptibility mapping remains a useful tool to evaluate PM pollution impact, yet its application potential across land use classes is limited.
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•3D magnetic soil variation was studied across different land use classes.•Land use affected magnetic susceptibility, limiting direct evaluation of pollution.•Magnetic susceptibility did not correlate with the distance to the pollution source.•Downhole measurements facilitated correct interpretation of topsoil magnetic maps.•Robust magnetic monitoring across various land use classes requires ancillary data.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
– Large scale geophysical prospection of an archaeological landscape in the Netherland. – Integrated and multimethodological approach for archaeological interpretation. – Challenges for the ...prospecting and interpretation of multiperiod archaeological sites.
The assessment of soil elemental concentrations nowadays mainly occurs through conventional laboratory analyses. However, proximal soil sensing (PSS) techniques such as X-ray fluorescence (XRF) ...spectrometry are proving to reduce analysis time and costs, and thus offer a worthy alternative to laboratory analyses. Moreover, XRF scanners are non-destructive and can be directly employed in the field. Although the use of XRF for soil elemental analysis is becoming widely accepted, most previous studies were limited to one scanner, a few samples, a few elements, or a non-diverse sample database. Here, an extensive and diverse soil database was used to compare the performance of three different XRF scanners with results obtained through conventional laboratory analyses. Scanners were used in benchtop mode with built-in soil calibrations to measure the concentrations of 15 elements. Although in many samples Cu, S, P, and Mg concentrations were up to 6, 12, 13, and 5 times overestimated by XRF, and empirical recalibration is recommended, all scanners produced acceptable results, even for lighter elements. Unexpectedly, XRF performance did not seem to depend on soil characteristics such as CaCO3 content. While performances will be worse when expanding to the field, our results show that XRF can easily be applied by non-experts to measure soil elemental concentrations reliably in widely different environments.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
– Electromagnetic induction survey was used to investigate the prehistoric landscape at Stonehenge. – Borehole logs and forward modelling were used to develop a semi-automated interpretation scheme. ...– Twenty excavations enabled the potential and limitations of the approach to be evaluated.
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