Search

A Correction to this paper has been published: https://doi.org/10.1038/s41558-021-00991-1.

In the version of this Analysis originally published, the following affiliation for A. Lohila was missing: ‘Finnish Meteorological Institute, Climate System Research, Helsinki, Finland’. This affiliation has now been added, and subsequent affiliations renumbered accordingly, in the online versions of the Analysis.

— Passive microwave L-band remote sensing is well known for its sensitivity to surface soil moisture over land. The signal is also affected by other dynamic variables such as vegetation and soil salinity. In this research, L-band microwave observations of the Soil Moisture Ocean Salinity (SMOS) mission are used to explore soil surface salinity, moisture and vegetation, in the Argentinean Dry Chaco, an area with possible emerging dryland salinity. A Radiative Transfer Model (RTM) with inclusion of a correction to the soil’s dielectric constant for salinity was used in forward and inverse mode, using either in situ data or Catchment Land Surface Model (CLSM) simulations as RTM input. The forward analysis pointed out shortcomings in the modeled soil moisture and soil surface temperature estimates. The impact of salinity on forward simulations over the Dry Chaco was limited. The RTM inversion using 10 years of SMOS brightness temperature observations resulted in realistic estimates of vegetation and roughness, both with and without optimizing a correction term for the dielectric constant in terms of salinity equivalents. However, the retrieval of the correction term to the dielectric constant was very uncertain and not representative of soil surface salinity, but rather of open water, texture uncertainty or soil moisture bias. © 2021 Institute of Electrical and Electronics Engineers Inc.. All rights reserved.

© 2020, The Author(s), under exclusive licence to Springer Nature Limited. The carbon balance of peatlands is predicted to shift from a sink to a source this century. However, peatland ecosystems are still omitted from the main Earth system models that are used for future climate change projections, and they are not considered in integrated assessment models that are used in impact and mitigation studies. By using evidence synthesized from the literature and an expert elicitation, we define and quantify the leading drivers of change that have impacted peatland carbon stocks during the Holocene and predict their effect during this century and in the far future. We also identify uncertainties and knowledge gaps in the scientific community and provide insight towards better integration of peatlands into modelling frameworks. Given the importance of the contribution by peatlands to the global carbon cycle, this study shows that peatland science is a critical research area and that we still have a long way to go to fully understand the peatland–carbon–climate nexus.

Introduction: In 2007, the Cancer Disease Hospital (CDH) was opened as the national referral center for patients diagnosed with cancer in Zambia. Since inception of the CDH, there has been no systematic analysis of the disease burden and implication on healthcare delivery with regards to pancreatic cancer. There are limited studies describing patterns of pancreatic cancer in a native African population. Data suggest African-Americans have a higher incidence and poorer prognosis of pancreatic cancer than non-African Americans.Objective: Our aim is to describe the demographic features (age, gender) of pancreatic cancer using the Cancer Disease Hospital (CDH) data base in a native African population and compare with the African-American cohort using the Surveillance, Epidemiology End Results (SEER) Program database.Methods: This was a retrospective study of patients diagnosed with pancreatic cancer at the CDH in Zambia, Southern Africa between 2007 and 2014. We entered the term “pancreatic cancer” into the CDH database, extracted patient medical records numbers, and manually located the records for review. From each chart we extracted: age, gender, geographic origin, ethnicity, clinical features at presentations, location of tumor, stage at diagnosis and treatment. Data collection tool and master code sheet created a priori were used. Data was analyzed using statistical analysis software (SAS). Descriptive statistics including means, medians as well as frequency distributions and crosstabulations were used. SEER database was used to compare subjects between Zambia and USA. Groups were compared using Chi-square tests and Wilcoxon Signed Rank test. Ap-value less than 0.05 was used as the level of significance.Results: Thirty-eight charts were identified in the CDH dataset, of which 27 were included in final analysis and 11 excluded (5 non-pancreatic cancer diagnosis, 6 not manually located). The mean age of diagnosis was 55.7 years in the native African population, compared to 66.7 years for the African-Americans in the SEER database, p < 0.0001. There were 63.0% males (CDH) compared to 48.1% (SEER), p=0.121. Further review of the CDH database revealed that the most common presenting symptom was abdominal pain (52.6%), mode of diagnosis surgical (83%, missing 3), histopathology adenocarcinoma (86%, missing 6), location head of pancreas (83%, missing 9) and stage 4 at diagnosis (100%, missing 3).Conclusion: Pancreatic cancer occurs at a younger age in Zambians when compared to the African American, USApopulation. There is no statistically significant difference in sex presentation between Zambian and USAblack population.

[Projektziel] Ziel des Projekts war es, deutschlandweit aktuelle Daten zu Flächen organischer Böden, Nutzung, Wasserständen und Treibhausgasemissionen zu erheben und somit die aktuelle Treibhausgasbilanz der organischen Böden in Deutschland zu quantifizieren.

The present study evaluated the relevance of EGFR overexpression in prediction of malignant transformation of oral leukoplakia (OLP). The retrospective study comprised paraffin-embedded tissue samples of OLP that transformed into oral squamous cell carcinoma (OSCC) (n=53) and tissue samples of OLP that did not transform into OSCC (n=45) during a follow-up period of 5 years. EGFR overexpression was assessed immunohistochemically. A significantly different expression rate of EGFR was determined between transformed and non-transformed OLP (P=0.017). A statistically significant increase of EGFR expression for low dysplasia lesions in group I compared to group II was proven (D0, P=0.013; D1, P=0.049). By calculation of ROC curve and determination of highest Youden index the optimal threshold value [cut-off point (COP) = 44.96] for distinguishing the transformed from non-transformed lesions was estimated (critical expression rate of EGFR). Using the determined COP the correlation between high-risk lesions and the detection of increased expression rates were significant (P=0.001). In the future, the assessment of EGFR overexpression in OLP may allow identifying OLP lesions with an increased risk of malignant transformation that may have been regarded harmless when only the grade of dysplasia had been taken into account.

Random walk particle tracking (RWPT) is a well established and efficient alternative to grid-based Eulerian approaches when simulating the advection-dispersion transport problem in highly heterogeneous porous media. However, RWPT methods suffer from a lack of accuracy when the dispersion tensor or the water content is spatially discontinuous. We present improvements to the concept of a partially reflecting barrier used to account for these discontinuities : (1) the nonlinear time splitting with root Delta t = root Delta t(1) vertical bar root Delta t(2) that corrects for the systematic overestimation of the second dispersion displacement across an element interface when linear time splitting is used; (2) the one-sided reflection coefficient that correctly represents the effect of discontinuous dispersion coefficients and water content but eliminates redundant reflections of the two-sided reflection coefficient and limits the error for discrete Delta t; and (3) the transformation of the dispersive displacement across the element interface for complex multidimensional transport problems. The proposed improvements are verified numerically by comparison with an analytical solution and a reference RWPT method. The results indicate an increased efficiency and accuracy of the new RWPT algorithm. Because the new algorithm efficiently simulates both advection- and dispersion-dominated transport conditions, it enhances the applicability of RWPT to scenarios in which both conditions occur, as, for example, in the highly transient unsaturated zone. The algorithm is easily implemented and it is shown that the computational benefit increases with increasing variability of the hydraulic parameter field.

We present results from solute transport experiments in an evaporating composite porous medium consisting of a cylindrical inner core with coarse sand that was surrounded by a mantle with fine sand. Small volumes of dye and salt tracer were applied at the surface of the fine material of the evaporating column. The pressure head at the bottom boundary was kept constant using a hanging water table ensuring liquid phase continuity to top surface in both fine and coarse material, whereby the latter was hydraulically less conductive at these pressure conditions. Contrary to the expectation that solute accumulation at an evaporating surface is proportional to local cumulative evaporation, high concentration spots developed at the surface of the coarse material, for which IR surface temperature measurements did not indicate higher evaporation fluxes. 3D unsaturated flow and transport simulations and a second tracer experiment monitored with magnetic resonance imaging (MRI) demonstrated that preferential upward water flux in the fine sand deeper in the column and near-surface lateral water flow from the fine into the coarse sand in combination with a downward diffusive flux are responsible for the local solute accumulation. We propose that at the wet regions of a soil surface, solute accumulation is largely decoupled from local evaporation fluxes and strongly governed by relative differences of the hydraulic conductivities. The possible formation of high solute concentration spots at the surface of coarser regions usually representing preferential flow pathways during strong precipitation may have an accelerating effect on the leaching of solutes. Citation: Bechtold, M., S. Haber-Pohlmeier, J. Vanderborght, A. Pohlmeier, T. P. A. Ferre, and H. Vereecken (2011), Near-surface solute redistribution during evaporation, Geophys. Res. Lett., 38, L17404, doi:10.1029/2011GL048147.