Hybrid driver-vehicle dynamics in microscopic modeling of traffic networks*

In this paper the microscopic traffic modeling framework proposed by the authors is enriched with a hybrid driver-vehicle model. The proposed framework models traffic networks exploring vehicle to vehicle and road to vehicle interactions. Vehicles are modeled as agents composed of simple vehicular dynamics controlled by a hybrid automaton representing the control that each driver applies to his vehicle to steer its dynamics. The continuous dynamics of the hybrid system implements a speed-position tracking control. The discrete event dynamics set the objective of the control according to the driving task chosen by the driver on the basis of the perceived environmental information

Photosynthesis in poor nutrient soils, in compacted soils, and under drought

Plants require the uptake of nutrients (in most cases via roots) and their incorporation into plant organs for growth. In non-woody species, 83% of fresh weight is water, 7% is carbon, 5% is oxygen, with the remaining 5% including hydrogen and such nutrients. In natural ecosystems, availability of nutrients in soils is heterogeneous, and many species often adapt their growth to the amount of nutrients that roots can take up by exploring the available soil volume. In agricultural areas, the lack of some nutrients is frequent. In both cases, plants must also face periods of drought and soil compaction. These environmental stresses are therefore not uncommon in natural ecosystems and crops, and the stressed plants often experience a decrease in photosynthetic CO2 fixation. In this chapter, we review changes observed in photosynthesis in response to nutrient deficiencies, soil compaction, and drought. The current knowledge on photosynthesis in carnivorous plants, as a special case of plant species growing in nutrient poor soils, is also included. Pigment limitations (chlorosis and/or necrosis), stomatal limitations, ultrastructural effects and mesophyll conductance limitations, photochemistry (primary reactions), carboxylation and Calvin-cycle reactions, and carbohydrate metabolism and transport will be discussed. With regard to nutrients, we have focused on the most common nutrition-related stresses in plants, the deficiencies of macro- (nitrogen, phosphorous, and potassium) and micronutrients (iron, manganese, copper, and zinc). Other nutrient deficiencies (or toxicities, both in the cases of essential nutrient excess or heavy metals) are not reviewed here. For other nutrient deficiencies and toxicities, and the role of the above-mentioned, and other nutrients (such as calcium and magnesium) in gas exchange, and as intracellular signal transducers, enzyme activators, and structure and function stabilizers of biological membranes, readers are referred to papers published elsewhere (Marschner H, Mineral nutrition of higher plants. Academic, London, 1995; Cakmak I, Kirkby EA, Physiol Plant 133:692–704, 2008; Morales F, Warren CR, Photosynthetic responses to nutrient deprivation and toxicities. In: Flexas J, Loreto F, Medrano H (eds) Terrestrial photosynthesis in a changing environment: a molecular, physiological and ecological approach. Cambridge University Press, Cambridge, pp 312–330, 2012; Hochmal AK, Schulze S, Trompelt K, Hippler M, Biochim Biophys Acta 1847:993–1003, 2015).This study was supported by the Spanish Ministry of Economy and Competitiveness (MINECO; projects AGL2012-31988, AGL2013-42175-R, AGL2016-75226-R, and AGL2016-79868-R, co-financed with FEDER), the Aragón Government (Group A03), grant LO1204 (Sustainable development of research in the Centre of the Region Haná) from the National Program of Sustainability I, and by the Czech Science Foundation Agency (project 16-07366Y). FM wishes to thank JC Martínez for his help with some periodic bibliographic searches.Peer reviewe