A stochastic–geometric model of the variability of soil formed in Pleistocene patterned ground

In this paper we develop a model for the spatial variability of apparent electrical conductivity, ECa, of soil formed in relict patterned ground. The model is based on the continuous local trend (CLT) random processes introduced by Lark (2012b) (Geoderma, 189–190, 661–670). These models are non-Gaussian and so their parameters cannot be estimated just by fitting a variogram model. We show how a plausible CLT model, and parameters for this model, can be found by the structured use of soil knowledge about the pedogenic processes in the particular environment and the physical properties of the soil material, along with some limited descriptive statistics on the target variable. This approach is attractive to soil scientists in that it makes the geostatistical analysis of soil properties an explicitly pedological procedure, and not simply a numerical exercise. We use this approach to develop a CLT model for ECa at our target site. We then develop a test statistic which measures the extent to which soils on this site with small values of ECa, which are coarser and so more permeable, tend to be spatially connected in the landscape. When we apply this statistic to our data we get results which indicate that the CLT model is more appropriate for the variable than is a Gaussian model, even after the transformation of the data. The CLT model could be used to generate training images of soil processes to be used for computing conditional distributions of variables at unsampled sites by multiple point geostatistical algorithms

Prevalence of Vocal Tract Discomfort in the Flemish Population Without Self-Perceived Voice Disorders.

OBJECTIVES: The main aim of this study was to assess the prevalence of Vocal Tract Discomfort (VTD) in the Flemish population without self-perceived voice disorders using the VTD scale and to examine the relationship between vocal load and VTD symptoms. In addition, consistency between the VTD scale and the Voice Handicap Index (VHI) and the Corporal Pain scale was evaluated. METHODS: A total of 333 participants completed the VTD scale, the VHI, and the Corporal Pain scale. Patient information about study and voice-related hobbies (for students), state of (non)professional voice user (for employees), smoking, shouting, allergy, and voice therapy was taken into account. RESULTS: A median number of three VTD symptoms was reported, and 88% of the participants showed at least one symptom of VTD. Dryness (70%), tickling (62%), and lump in the throat (54%) were the most frequently occurring symptoms. The frequency and severity of VTD were significantly higher in participants who followed voice-related studies, played a team sport, were part of a youth movement, shouted frequently, and received voice therapy in the past (P < 0.05). Finally, low correlations were obtained between frequency and severity of the VTD scale and total VHI score (r = 0.226-0.411) or frequency and intensity of the Corporal Pain scale (r = 0.016-0.408). CONCLUSIONS: The prevalence of VTD is relatively high in the Flemish population without self-perceived voice disorders, although the frequency and severity of the symptoms are rather low. Vocal load seems to influence the frequency and severity of VTD. Finally, the VTD scale seems to reveal clinically important information that cannot be gathered from any other protocol