Analysis of a heterogeneous kinetic model for traffic flow

In this work we extend a recent kinetic traffic model to the case of more than one class of vehicles, each of which is characterized by few different microscopic features. We consider a Boltzmann-like framework with only binary interactions, which take place among vehicles belonging to the various classes. Our approach differs from the multi-population kinetic model based on a lattice of speeds because here we assume continuous velocity spaces and we introduce a parameter describing the physical velocity jump performed by a vehicle that increases its speed after an interaction. The model is discretized in order to investigate numerically the structure of the resulting fundamental diagrams and the system of equations is analyzed by studying well posedness. Moreover, we compute the equilibria of the discretized model and we show that the exact asymptotic kinetic distributions can be obtained with a small number of velocities in the grid. Finally, we introduce a new probability law in order to attenuate the sharp capacity drop occurring in the diagrams of traffic.Comment: 31 page

Fundamental diagrams in traffic flow: the case of heterogeneous kinetic models

Experimental studies on vehicular traffic provide data on quantities like density, flux, and mean speed of the vehicles. However, the diagrams relating these variables (the fundamental and speed diagrams) show some peculiarities not yet fully reproduced nor explained by mathematical models. In this paper, resting on the methods of kinetic theory, we introduce a new traffic model which takes into account the heterogeneous nature of the flow of vehicles along a road. In more detail, the model considers traffic as a mixture of two or more populations of vehicles (e.g., cars and trucks) with different microscopic characteristics, in particular different lengths and/or maximum speeds. With this approach we gain some insights into the scattering of the data in the regime of congested traffic clearly shown by actual measurements.Comment: 26 pages, 11 figure

Analysis of a multi-population kinetic model for traffic flow

In this work we extend a recent kinetic traffic model [G. Puppo, M. Semplice, A. Tosin, G. Visconti, Kinet. Relat. Models, in press, 2016] to the case of more than one class of vehicles, each of which is characterized by few different microscopic features. We consider a Boltzmann-like framework with only binary interactions, which take place among vehicles belonging to the various classes. Our approach differs from the multi-population kinetic model proposed in [G. Puppo, M. Semplice, A. Tosin, G. Visconti, Commun. Math. Sci., 14:643-669, 2016] because here we assume continuous velocity spaces and we introduce a parameter describing the physical velocity jump performed by a vehicle that increases its speed after an interaction. The model is discretized in order to investigate numerically the structure of the resulting fundamental diagrams and the system of equations is analyzed by studying well posedness. Moreover, we compute the equilibria of the discretized model and we show that the exact asymptotic kinetic distributions can be obtained with a small number of velocities in the grid. Finally, we introduce a new probability law in order to attenuate the sharp capacity drop occurring in the diagrams of traffic

Quality evaluation of gluten-free biscuits prepared with algarrobo flour as a partial sugar replacer

Algarrobo flour is a gluten-free flour obtained by grinding the whole fruit (pods) of Prosopis chilensis. Because of its taste, this flour could be used as a sugar replacer. Besides, it can improve the protein profile, and the antioxidant and fibre content of foodstuffs. This is of special interest in gluten-free products that are generally deficient in these nutrients. In the present work a total of eleven different gluten-free biscuit formulations with Algarrobo flour and different proportions of rice flour, chickpea flour, cassava starch, and maize starch were evaluated. The effects of each ingredient were analysed and the texture, colour, total dietary fibre content, antioxidant capacity, and sensorial acceptability associated with the addition of algarrobo flour as a partial sugar replacer were studied in detail in three selected formulations. Results showed that the dietary fibre content and the antioxidant capacity increased with the addition of algarrobo flour (60 and 20%, respectively). In addition, no significant differences were found in the sensory scores of biscuits prepared with sugar or with algarrobo flour (P ≥ 0.05). It could be concluded that algarrobo flour could partially replace sugar in gluten-free biscuit formulations. Besides, its addition increases the fibre and antioxidant capacity of the product without significantly changing its optimum texture. This is a major achievement that could be the starting point for future research aimed to develop new and healthy gluten-free products.Fil: Lanata, M. C.. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Patrignani, Mariela. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Puppo, Maria Cecilia. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales; ArgentinaFil: Conforti, Paula Andrea. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales; Argentin

Serum 27-hydroxycholesterol in patients with primary biliary cirrhosis suggests alteration of cholesterol catabolism to bile acids via the acidic pathway

Reduced cholesterol synthesis has been reported in patients with primary biliary cirrhosis but no data are available on changes in cholesterol catabolism induced by the disease. Serum levels of 7α-hydroxycholesterol and 27-hydroxycholesterol have been measured in 25 patients (either normocholesterolemic or hypercholesterolemic) with primary biliary cirrhosis and in control subjects. To evaluate cholesterol synthesis, serum levels of lathosterol were measured, and campesterol and sitosterol were considered to reflect intestinal absorption and biliary elimination of sterols. In normocholesterolemic patients with primary biliary cirrhosis, lathosterol was significantly lower than in normocholesterolemic controls (P < 0.05) whereas no difference was found between hypercholesterolemic patients and hypercholesterolemic controls. Serum concentrations of sitosterol were significantly higher in both normocholesterolemic and hypercholesterolemic patients with primary biliary cirrhosis as compared with the respective controls (P < 0.01). In patients with primary biliary cirrhosis, serum 7α-hydroxycholesterol was slightly higher than in controls. 27-Hydroxycholesterol was significantly higher in hypercholesterolemic compared to normocholesterolemic controls (P < 0.05) and a significant linear correlation (r = 0.771; P < 0.001) was found between 27-hydroxycholesterol and cholesterol. In contrast, in patients with primary biliary cirrhosis, high cholesterol concentrations were not associated with increased serum levels of 27-hydroxycholesterol. Our data confirm that in patients with primary biliary cirrhosis, cholesterol synthesis and biliary elimination of sterols are impaired and also suggest that both the feedback regulation of retained bile acids on cholesterol 7α-hydroxylase and the scavenger effect on elevated serum cholesterol by cholesterol 27-hydroxylase are deficient in these patients.—Del Puppo, M., M. Galli Kienle, M. L. Petroni, A. Crosignani, and M. Podda. Serum 27-hydroxycholesterol in patients with primary biliary cirrhosis suggests alteration of cholesterol catabolism to bile acids via the acidic pathway. J. Lipid Res. 1998. 39: 2477–2482

Casas, gérmenes y virus: Episodios de eclosión entre la enfermedad y el habitar

La casa se enferma, la casa nos enferma, la casa cura, la casa nos cura. La hipótesis de la vivienda como lugar donde se curan trastornos médicos y sociales es el punto de partida del presente artículo. El objetivo planteado es analizar, a través de tres episodios, la modernidad incipiente de la segunda mitad del siglo XIX, la modernidad hegemónica de la primera mitad del siglo XX y la contemporaneidad, la relación entre vivienda y enfermedad. En el combate a las enfermedades la arquitectura ha encontrado una excusa para repensar y reformular los paradigmas vigentes del habitar, y a inicios del siglo XXI nuevamente se enfrenta a este desafío disciplinar en el marco de la pandemia por el COVID-19, que ha evidenciado el conflicto ya existente entre las necesidades contemporáneas y un paradigma habitacional deudor de la modernidad.La casa se enferma, la casa nos enferma, la casa cura, la casa nos cura. La hipótesis de la vivienda como lugar donde se curan trastornos médicos y sociales es el punto de partida del presente artículo. El objetivo planteado es analizar, a través de tres episodios, la modernidad incipiente de la segunda mitad del siglo XIX, la modernidad hegemónica de la primera mitad del siglo XX y la contemporaneidad, la relación entre vivienda y enfermedad. En el combate a las enfermedades la arquitectura ha encontrado una excusa para repensar y reformular los paradigmas vigentes del habitar, y a inicios del siglo XXI nuevamente se enfrenta a este desafío disciplinar en el marco de la pandemia por el COVID-19, que ha evidenciado el conflicto ya existente entre las necesidades contemporáneas y un paradigma habitacional deudor de la modernidad