Agricultural activity shapes the communication and migration patterns in Senegal.

The communication and migration patterns of a country are shaped by its socioeconomic processes. The economy of Senegal is predominantly rural, as agriculture employs over 70% of the labor force. In this paper, we use mobile phone records to explore the impact of agricultural activity on the communication and mobility patterns of the inhabitants of Senegal. We find two peaks of phone calls activity emerging during the growing season. Moreover, during the harvest period, we detect an increase in the migration flows throughout the country. However, religious holidays also shape the mobility patterns of the Senegalese people. Hence, in the light of our results, agricultural activity and religious holidays are the primary drivers of mobility inside the country.

Mathematical decision theory applied to land capability: a case study in the community of madrid.

In land evaluation science, a standard data set is obtained for each land unit to determine the land capability class for various uses, such as different farming systems, forestry, or the conservation or suitability of a specific crop. In this study, we used mathematical decision theory (MDT) methods to address this task. Mathematical decision theory has been used in areas such as management, finance, industrial design, rural development, the environment, and projects for future welfare to study quality and aptness problems using several criteria. We also review MDT applications in soil science and discuss the suitability of MDT methods for dealing simultaneously with a number of problems. The aim of the work was to show how MDT can be used to obtain a valid land quality index and to compare this with a traditional land capability method. Therefore, an additive classification method was applied to obtain a land quality index for 122 land units that were compiled for a case study of the Community of Madrid, Spain, and the results were compared with a previously assigned land capability class using traditional methods based on the minimum requirements for land attributes.

Spatial characterization of landscapes through multifractal analysis of DEM.

Landscape evolution is driven by abiotic, biotic, and anthropic factors. The interactions among these factors and their influence at different scales create a complex dynamic. Landscapes have been shown to exhibit numerous scaling laws, from Horton's laws to more sophisticated scaling of heights in topography and river network topology. This scaling and multiscaling analysis has the potential to characterise the landscape in terms of the statistical signature of the measure selected. The study zone is a matrix obtained from a digital elevation model (DEM) (map 10 × 10 m, and height 1 m) that corresponds to homogeneous region with respect to soil characteristics and climatology known as "Monte El Pardo" although the water level of a reservoir and the topography play a main role on its organization and evolution. We have investigated whether the multifractal analysis of a DEM shows common features that can be used to reveal the underlying patterns and information associated with the landscape of the DEM mapping and studied the influence of the water level of the reservoir on the applied analysis. The results show that the use of the multifractal approach with mean absolute gradient data is a useful tool for analysing the topography represented by the DEM.

Fractal analysis of laplacian pyramidal filters applied to segmentation of soil images.

The laplacian pyramid is a well-known technique for image processing in which local operators of many scales, but identical shape, serve as the basis functions. The required properties to the pyramidal filter produce a family of filters, which is unipara metrical in the case of the classical problem, when the length of the filter is 5. We pay attention to gaussian and fractal behaviour of these basis functions (or filters), and we determine the gaussian and fractal ranges in the case of single parameter a. These fractal filters loose less energy in every step of the laplacian pyramid, and we apply this property to get threshold values for segmenting soil images, and then evaluate their porosity. Also, we evaluate our results by comparing them with the Otsu algorithm threshold values, and conclude that our algorithm produce reliable test results.

Multifractal analysis of tori destruction in a molecular Hamiltonian system.

In this paper, an analysis of the phase space structure of the isomerizing molecular system LiNC/LiCN, using Poincaré surfaces of section and frequency analysis, is presented. The scaling structure of the frequency map in the chaotic region next to the regular part corresponding to the stable linear isomer LiNC is studied using multifractal analysis. This approach is a way to characterize quantitatively the complexity in the mechanism of the tori destruction in a molecular Hamiltonian system that exhibits soft chaos as the vibrational energy of the system increases.

Influence of pyrolysis temperature on composted sewage sludge biochar priming effect in a loamy soil.

Biochar is a carbon-rich solid product obtained by the pyrolysis of organic materials. The carbon stability of biochar allows that it can be applied to soil for long-term carbon storage. This carbon stability is greatly influenced by the pyrolysis temperature and the raw material used for biochar production. The aim of the present work is to study the soil carbon sequestration after the application of biochar from sewage sludge (SL) pyrolysis at two different temperatures (400 and 600 °C). For this purpose, soil CO2 emissions were measured for 80 d in an incubation experiment after soil amendment with the SL and each biochar at a dosage of 8 wt%. Biochar reduced the CO2 emissions during incubation between 11% and 32% relative to the SL treatment. The CO2 data were fit to a dual exponential model, and the CO2 emissions were simulated at different times (1, 5 and 10 yr). Additionally, the kinetics of the CO2 evolution from SL, two biochar samples, soil and amended soil were well fit to a dual first-order kinetic model with correlation coefficients greater than 0.93. The simulation of CO2 emissions from the soil by applying the proposed double first-order kinetic model (kg CO2-C ha(-1)) showed a reduction of CO2 emissions between 301 and 932 kg CO2-C ha(-1)with respect to the direct application of raw sewage sludge after 10 yr.