Narrow Results

The relationship between the producer and the consumer is important in grassland ecosystems. Most producer-consumer models only consider food quantity and focus on the above ground part of producers in producer-consumer interactions, while food quality and the below ground part of the producer can be an important factor in these models. We developed a stoichiometric producer-consumer model, where the producer represents a primary production in terrestrial plant with above ground and below ground parts subject to stoichiometric constraints of carbon and phosphorus. The analysis shows that the dynamic behavior of the model is richer than that of the traditional producer-consumer models. The solution curves of the model can be used to explain the paradox of enrichment and reflect the rapid growth of the vegetation. Our findings help understand and interpret the relationship between the producer and the consumer in grassland ecosystems and provide guidance for ecosystem management on maintaining ecological equilibrium.

CuInSe₂ thin films were grown by vacuum evaporation of presynthesized material from a single source. The room-temperature photoconductivity spectra of the film show a strongly dependence on the evaporation conditions and, especially, on the evaporation temperature. A shift of the long-wavelenght photoactive absorption edge and the evolution of the photoconductivity spectra of the films were observed. The influence can be explained by allowing for deviations of the compositions of the condensed phase from CuInSe₂ stoichiometry.

Some people think that carbon and sustainable development are not compatible. This textbook shows that carbon dioxide (CO₂) from the air and bio-carbon from biomass are our best allies in the energy transition, towards greater sustainability. We pose the problem of the decarbonation (or decarbonization) of our economy by looking at ways to reduce our dependence on fossil carbon (coal, petroleum, natural gas, bitumen, carbonaceous shales, lignite, peat). The urgent goal is to curb the exponential increase in the concentration of carbon dioxide in the atmosphere and hydrosphere (Figures 1.1 and 1.2) that is directly related to our consumption of fossil carbon for our energy and materials The goal of the Paris agreement (United Nations COP 21, Dec. 12, 2015) of limiting the temperature increase to 1.5 degrees (compared to the pre-industrial era, before 1800) is becoming increasingly unattainable (Intergovermental Panel on Climate Change (IPCC), report of Aug. 6, 2021). On Aug. 9, 2021 Boris Johnson, prime minister of the United Kingdom, declared that coal needs to be consigned to history to limit global warming. CO₂ has an important social cost…