Time for non-illuvial Bt horizons?

The Bt horizon is the diagnostic horizon of the Luvisolic Order in Canada. According to the Canadian System of Soil Classification (CSSC), the Bt must be formed from clay illuviation through the processes of lessivage (i.e., physical transport of clay). In a study of a Luvisol catena in the central Saskatchewan, we demonstrate that Ae/Bm horizons overlying IIBt horizons are formed in a sandy mantle overlying till (i.e., a lithological discontinuity) and that the sandy mantle contributed negligible amounts of illuvial clay despite the presence of clay skins on ped surfaces in the IIBt horizon. We extended the results of this study to the regional scale by examining sand fractions in 63 pedons of Luvisol-dominated soil associations from soil surveys in the Northern Forest Reserves (between latitudes 53^oN and 55^oN). Of the 63 pedons, 13 had lithological discontinuities identified in their profile description and a further 27 had discontinuities identified through shifts in the sand fractions between horizons. For the profiles with discontinuities, inherited particle size differences are a more likely cause of coarse-over-fine textural contrasts than lessivage. A regional analysis of the distribution of Luvisol-dominated associations showed distinct zonations that account, in part, for the differences in the occurrence of lithological discontinuities. Based on these results, we suggest that the criteria for Bt horizons in the CSSC should be broadened to include non-illuvial coarse-over-fine texture-contrast horizons and that the criteria for the Luvisolic order also be broadened to include these non-illuvial Bt horizons.

"LeukNet" - A Model of Convolutional Neural Network for the Diagnosis of Leukemia

Leukemia is a disorder that affects the bone marrow, causing uncontrolled production of leukocytes, impairing the transport of oxygen and causing blood coagulation problems. In this article, we propose a new computational tool, named LeukNet, a Convolutional Neural Network (CNN) architecture based on the VGG-16 convolutional blocks, to facilitate the leukemia diagnosis from blood smear images. We evaluated different architectures and fine-tuning methods using 18 datasets containing 3536 images with distinct characteristics of color, texture, contrast, and resolution. Additionally, data augmentation operations were applied to increase the training set by up to 20 times. The k-fold cross-validation (k = 5) results achieved 98.28% of accuracy. A cross-dataset validation technique, named LeaveOne-Dataset-Out Cross-Validation (LODOCV), is also proposed to evaluate the developed model’s generalization capability. The accuracy of using LODOCV on the ALL-IDB 1, ALL-IDB 2, and UFG datasets was 97.04%, 82.46%, and 70.24%, respectively, overcoming the current state-of-the-art results and offering new guidelines for image-based computer-aided diagnosis (CAD) systems in this area.

The Use of Texture Features to Extract and Analyze Useful Information from Retinal Images

Background: The analysis of retinal images can help to detect retinal abnormalities that are caused by cardiovascular and retinal disorders. Objective: In this paper, we propose methods based on texture features for mining and analyzing information from retinal images. Methods: The recognition of the retinal mask region is a prerequisite for retinal image processing. However, there is no way to automatically recognize the retinal region. By quantifying and analyzing texture features, a method is proposed to automatically identify the retinal region. The boundary of the circular retinal region is detected based on the image texture contrast feature, followed by the filling of the closed circular area, and then the detected circular retinal mask region can be obtained. Results: The experimental results show that the method based on the image contrast feature can be used to detect the retinal region automatically. The average accuracy of retinal mask region detection of images from the Digital Retinal Images for Vessel Extraction (DRIVE) database was 99.34%. Conclusion: This is the first time these texture features of retinal images are analyzed, and texture features are used to recognize the circular retinal region automatically.

Beneficial soil profile differences associated with tropical grass pastures on sodic texture contrast soils in Northern New South Wales

Volunteer native pastures on widespread sodic texture contrast soils in northern New South Wales slopes and plains are known for their limited agricultural production. Fertilised tropical grass pastures on these soils are reported to have much increased pasture production, deeper, more abundant root mass and greater soil profile moisture storage. The subsoil physical differences between native and tropical grass pastures are not well understood. This observational study compared root abundance, soil structure and soil physical parameters (dispersion, bulk density, porosity and pore distribution) in sodic texture contrast soils under native and adjacent, well established and fertilised tropical pastures in a 14-year chronosequence. The physical differences observed may have contributed to improved soil water storage reported by other authors. Fourteen years after establishment, mean root abundance was significantly lower in soils under native pasture and greater in the tropical grass pasture system with 4600 and 8400 m of roots m–3 respectively. Dispersion values were high in native pastures but soils under tropical pastures had to be physically worked to cause dispersion. Bulk density under native pasture was significantly higher than in tropical grass pastures by 0.08 g cm–3 at 0–10 cm and by 0.2 g cm–3 in the upper B horizons. Total soil porosity of topsoils and upper B horizons was consequently lower in native than in tropical grass pasture. Tropical grass pasture upper B horizons had a three-fold greater macroporosity (pores > 30 µm), than under native pastures. This is equivalent to significantly greater potential water flow through stable macropores in dense sodic B horizons in tropical pastures. These findings indicate that pasture system selection and management positively affects deep soil structural properties which promote pasture productivity. The study contributes to a better understanding of mechanisms of published deeper water storage in tropical grass pasture systems on these normally low production soils.

The Contribution of Texture Contrasts and Combinations to Food Acceptance Across Cultures

Texture has long been considered an important attribute for food acceptance. However, which specific textural characteristics contribute to overall acceptance of a food is not well understood. It has been suggested that texture contrasts and combinations are a universal feature in giving foods a desirable texture, yet this notion is largely based upon anecdotal data. This study uses multiple survey research methods to assess the importance of texture contrast and combinations across cultures (Poland, U.S.A., and Singapore). Participants (n = 288) completed a survey that included overt measures of food texture contrast importance as well as free response questions regarding texture. The overall importance of texture for food liking was not different across the populations. However, the participants from Singapore and Poland gave more importance to a desirable food having multiple textures than the U.S.A. cohort. When looking at free responses, participants were twice as likely to mention combinations (multiple textures) with a texture contrast when describing foods they liked, in comparison to foods they disliked. This was observed across all 3 cultures. However, the type and quantity of texture terms used within combinations were different among cultures. For instance, Asians enjoyed more texturally diverse food combinations than the other two cultures. These findings highlight the importance of texture contrasts and combinations in three distinct cultures.

Second-Order Reversed Phi

A second-order reversed-phi stimulus is composed of moving features (areas filled with texture) whose overall amount of texture-contrast is reversed between successive frames. In peripheral vision, the stimulus is perceived as moving in the reversed direction (opposite to the feature displacement). In central vision, it is perceived in the forward direction at low temporal frequencies but in the reversed direction at high temporal frequencies. Moving the observer away from the displays has the same effect as changing from central to periphery vision: reversed motion becomes more dominant. The illusion demonstrates the different properties of the second- and third-order motion systems.

Second-Order Mach Bands, Chevreul, and Craik-O’Brien-Cornsweet Illusions

Second-order texture illusions, corresponding to Mach bands, Chevreul, and Craik-O’Brien-Cornsweet illusions in brightness perception, are generated by replacing luminance modulations in the classic stimuli with modulations of texture contrast. Whereas the classic (first-order) illusions exhibit changes in lightness or darkness near boundaries, the second-order stimuli exhibit analogous perceptual effects that are increases or decreases in apparent texture contrast with no concomitant change in apparent brightness. The magnitudes of the second-order texture-contrast changes are comparable to brightness changes in the classic first-order illusions. These results indicate that second-order (texture) illusions involve spatial interactions that are remarkably similar to those in first-order (luminance) processing.