Question
To assess the acidification process, nationwide information about soil pH on a site level is called for. Measurements of soil pH may be used, however there are not sufficient measurements ...available to map soil pH nationwide on site level. Instead we developed a soil pH map based on vegetation data.
Location
Natural terrestrial areas in The Netherlands.
Methods
271,693 vegetation plots were used to estimate average soil pH per plot with indicator values, based on field measurements, of plant species. By spatial interpolation average pH values between the plots, with the soil type, groundwater table and vegetation management type as ancillary explanatory variables we created a soil pH map. The map covers all terrestrial nature areas (all areas that are not built up areas, agricultural areas and infrastructural areas) in the Netherlands with a map resolution of 25 × 25 m2 raster cells.
Results
The predicted pH of the map varied between 3.0 and 8.6 with standard errors between 0.13 and 0.93. Most of the standard errors range from 0.4 to 0.55, with an average just below 0.5 pH unit. Cross‐validation shows that for 33% the difference between observed and predicted is between −0.1 and 0.1 pH‐unit and for 83% the difference is between −0.5 and 0.5 pH‐unit. Validation shows that the pH map is unbiased (mean error is almost zero), accurate (root mean squared error is 0.64) and nicely captures spatial patterns (r = 0.77). We applied the pH map to assess the impact of acidification on the abiotic quality of nature areas in the Netherlands.
Conclusions
The model fit in the predicted soil pH is in good resulting in a low standard error and a high correlation. The measures taken to prevent acidic deposition causing further acidifying of nature areas can be considered as successful.
Soil pH is one of the determining factors for species occurrence and therefore species can be used to reveal information about the soil pH. For the Netherlands over 200,000 plots are available to estimate soil pH and these estimated pH values were used to make a pH map for Dutch nature areas.
Background Groin pain is a frequent complaint in surgical practice with an inguinal hernia being at the top of the differential diagnosis. The majority of inguinal hernias can be diagnosed ...clinically. However, patients with groin pain without signs of an inguinal hernia on anamnesis or physical examination provide a diagnostic challenge. If ultrasonography shows a hernia that could not be detected clinically, this entity is called a clinically occult hernia. It is debatable if this radiological hernia is the cause of complaints in all patients with inguinal pain. The objective of this study is to assess whether watchful waiting is non-inferior to endoscopic totally extraperitoneal (TEP) inguinal repair in patients with a clinically occult inguinal hernia. Methods The EFFECT study is a multicenter non-blinded randomized controlled non-inferiority trial. Adult patients with unilateral groin pain and a clinically occult inguinal hernia are eligible to participate in this study. A total of 160 participants will be included and randomized to TEP inguinal hernia repair or a watchful waiting approach. The primary outcome of this study is pain reduction 3 months after treatment, measured by the Numeric Rating Scale (NRS). Secondary outcomes are quality of life, cost-effectiveness, patient satisfaction and crossover rate. Eight surgical centers will take part in the study. Participants will be followed-up for 1 year. Discussion This is the first large randomized controlled trial comparing treatments for patients with groin pain and a clinically occult inguinal hernia. To date, there are no interventional studies on the effect of surgery or a watchful waiting approach in terms of pain or quality of life in this subset of patients. A trial comparing the outcomes of the two approaches in patients with a clinically occult inguinal hernia is urgently needed to provide data facilitating the choice between the two treatment options. If watchful waiting is not inferior to surgical repair, costs of surgical repair may be saved. Trial registration The study protocol (NL61730.100.17) is approved by the Medical Ethics Committee (MEC-U) of the Diakonessenhuis, Utrecht, The Netherlands. The study was registered at the Netherlands Trial Registry (NTR6835) registered on November 13, 2017. Keywords: Inguinal hernia, Clinically occult, TEP, Watchful waiting, Pain, Quality of life, Cost-effectiveness
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