Message passing and Monte Carlo algorithms: connecting fixed points with metastable states

Mean field-like approximations (including naive mean field, Bethe and Kikuchi and more general Cluster Variational Methods) are known to stabilize ordered phases at temperatures higher than the thermodynamical transition. For example, in the Edwards-Anderson model in 2-dimensions these approximations predict a spin glass transition at finite $T$. Here we show that the spin glass solutions of the Cluster Variational Method (CVM) at plaquette level do describe well actual metastable states of the system. Moreover, we prove that these states can be used to predict non trivial statistical quantities, like the distribution of the overlap between two replicas. Our results support the idea that message passing algorithms can be helpful to accelerate Monte Carlo simulations in finite dimensional systems.Comment: 6 pages, 6 figure

Langevin dynamics of fluctuation induced first order phase transitions: self consistent Hartree Approximation

The Langevin dynamics of a system exhibiting a Fluctuation Induced First Order Phase Transition is solved within the self consistent Hartree Approximation. Competition between interactions at short and long length scales gives rise to spatial modulations in the order parameter, like stripes in 2d and lamellae in 3d. We show that when the time scale of observation is small compared with the time needed to the formation of modulated structures, the dynamics is dominated by a standard ferromagnetic contribution plus a correction term. However, once these structures are formed, the long time dynamics is no longer pure ferromagnetic. After a quench from a disordered state to low temperatures the system develops growing domains of stripes (lamellae). Due to the character of the transition, the paramagnetic phase is metastable at all finite temperatures, and the correlation length diverges only at T=0. Consequently, the temperature is a relevant variable, for $T>0$ the system exhibits interrupted aging while for T=0 the system ages for all time scales. Furthermore, for all $T$, the exponent associated with the aging phenomena is independent of the dimension of the system.Comment: 16 pages, 1 figur

Development and Assessment of a Groundwater Sustainability Index in Climatically Diverse Groundwater Irrigated Regions in Nebraska

The aim of this research was to evaluate the impact of regional change in ET on groundwater level changes and the assessment and development of a groundwater sustainability index for climatically diverse regions across Nebraska during 2000-2014. Irrigation in the selected regions is predominantly supplied by groundwater. The hypothesis is that groundwater use can become sustainable if the regional evapotranspiration (ET) is managed so that it equals the ET of vegetation that is native to the region. Site locations were Box Butte, Chase, Dundy, Holt LNNRD and York Counties and 3 ecosystems were evaluated: native vegetation, dryland and irrigated cropping systems. Methodology consisted of remote sensing data analysis, GIS modeling, ASCE-Penman Monteith Evapotranspiration equation (Allen et al., 2005) and analysis of historical data. Precipitation, ET, NDVI, Kc and ET weighed to obtain county average ET .Groundwater level declines and groundwater storage data were assessed and compared with ET. Also the same procedures were applied at the township scale for 5 townships in each county. Results showed that precipitation increased from west to east ranging between 406-693 mm.y-1. York County had the overall highest ET values, and Box Butte County had the lowest. Annual native vegetation ET ranged 382-644 mm.y-1 and county annual ET ranged 415-720 mm.y-1 from west to east. The highest groundwater level declines were in Box Butte, Dundy and York Counties (0.26 m.y-1) and the lowest in Holt LNNRD (0.12 m.y-1).Sustainability index (SI) indicated that Holt LNNRD was the most sustainable in water use (SI=0.94) and Chase County the least sustainable (SI=0.88). County average ET exceeded native vegetation ET in all cases due to the higher ET of irrigated crops. The positive correlation between ET increases and reduction in water storage showed a significant correlation (0.62) at p-value \u3c 0.05 level confidence, n=10. Higher SI resulted in lower reduction in groundwater storage. The negative correlation between SI and reduction in groundwater storage (-0.69) proved to be significant at p-value\u3c 0.025, n=10. However, data suggested that reducing county average ET, approaching that of native vegetation, which kept water levels in balance in the past, could be a promising practice. Advisor: Dean E. Eisenhaue

Development and Assessment of a Groundwater Sustainability Index in Climatically Diverse Groundwater Irrigated Regions in Nebraska

The aim of this research was to evaluate the impact of regional change in ET on groundwater level changes and the assessment and development of a groundwater sustainability index for climatically diverse regions across Nebraska during 2000-2014. Irrigation in the selected regions is predominantly supplied by groundwater. The hypothesis is that groundwater use can become sustainable if the regional evapotranspiration (ET) is managed so that it equals the ET of vegetation that is native to the region. Site locations were Box Butte, Chase, Dundy, Holt LNNRD and York Counties and 3 ecosystems were evaluated: native vegetation, dryland and irrigated cropping systems. Methodology consisted of remote sensing data analysis, GIS modeling, ASCE-Penman Monteith Evapotranspiration equation (Allen et al., 2005) and analysis of historical data. Precipitation, ET, NDVI, Kc and ET weighed to obtain county average ET .Groundwater level declines and groundwater storage data were assessed and compared with ET. Also the same procedures were applied at the township scale for 5 townships in each county. Results showed that precipitation increased from west to east ranging between 406-693 mm.y-1. York County had the overall highest ET values, and Box Butte County had the lowest. Annual native vegetation ET ranged 382-644 mm.y-1 and county annual ET ranged 415-720 mm.y-1 from west to east. The highest groundwater level declines were in Box Butte, Dundy and York Counties (0.26 m.y-1) and the lowest in Holt LNNRD (0.12 m.y-1).Sustainability index (SI) indicated that Holt LNNRD was the most sustainable in water use (SI=0.94) and Chase County the least sustainable (SI=0.88). County average ET exceeded native vegetation ET in all cases due to the higher ET of irrigated crops. The positive correlation between ET increases and reduction in water storage showed a significant correlation (0.62) at p-value \u3c 0.05 level confidence, n=10. Higher SI resulted in lower reduction in groundwater storage. The negative correlation between SI and reduction in groundwater storage (-0.69) proved to be significant at p-value\u3c 0.025, n=10. However, data suggested that reducing county average ET, approaching that of native vegetation, which kept water levels in balance in the past, could be a promising practice. Advisor: Dean E. Eisenhaue

Cyber-Physical Systems for Micro-/Nano-assembly Operations: a Survey

Abstract Purpose of Review Latest requirements of the global market force manufacturing systems to a change for a new production paradigm (Industry 4.0). Cyber-Physical Systems (CPS) appear as a solution to be deployed in different manufacturing fields, especially those with high added value and technological complexity, high product variants, and short time to market. In this sense, this paper aims at reviewing the introduction level of CPS technologies in micro/nano-manufacturing and how these technologies could cope with these challenging manufacturing requirements. Recent Findings The introduction of CPS is still in its infancy on many industrial applications, but it actually demonstrates its potential to support future manufacturing paradigm. However, only few research works in micro/nano-manufacturing considered CPS frameworks, since the concept barely appeared a decade ago. Summary Some contributions have revealed the potential of CPS technologies to improve manufacturing performance which may be scaled to the micro/nano-manufacturing. IoT-based frameworks with VR/AR technologies allow distributed and collaborative systems, or agent-based architectures with advance algorithm implementations that improve the flexibility and performance of micro-/nano-assembly operations. Future research of CPS in micro-/nano-assembly operations should be followed by more studies of its technical deployment showing its implications under other perspectives, i.e. sustainable, economic, and social point of views, to take full advance of all its features

Simulating human digestion: developing our knowledge to create healthier and more sustainable foods

The gold standard for nutrition studies is clinical trials but they are expensive and variable, and do not always provide the mechanistic information required, hence the increased use of in vitro and increasingly in silico simulations of digestion. In this review, we give examples of the main simulations being used to model upper gastrointestinal tract digestion. This review ranges from the selection of enzymes to the interpretation of results from static models to fully dynamic models. We describe the modifications made to accommodate different demographic groups (infants, the elderly, etc.). We list examples of the application of the different models as well as giving the advantages and disadvantages. A model is only useful if it predicts or aids the understanding of physiological behaviour. Thus, the final section of the review makes a comparison of results obtained from experiments undertaken using in vitro simulations with those obtained in vivo. This comparison will help the reader understand the appropriateness of each model for the type of measurement to be undertaken. In particular, human studies tend to measure bioactive concentrations in blood and not in the gastrointestinal tract whereas in vitro studies often only produce data on release of nutrients into the gut lumen. This is the difficulty of comparing bioaccessibility as generated in vitro with bioavailability as generated in vivo. It is apparent that the models being used are increasingly being validated with in vivo data and this bodes well for the future

Modeling Ultrasonically Assisted Convective Drying of Eggplan

[EN] Modeling constitutes a fundamental tool with which to analyze the influence of ultrasound on mass transfer phenomena during drying. In this work, the study of the effect of power ultrasound application on the drying kinetics of eggplant was addressed by using different models based on theoretical (diffusion) or empirical approaches. Drying kinetics of eggplant cylinders (height 20mm and diameter 24 mm) were carried at 40°C and 1 m/s applying different ultrasonic powers: 0, 6, 12, 19, 25, 31, and 37 kW/m 3. The experiments were carried out at least three times at each different ultrasonic power. Shrinkage and sorption isotherms were also addressed in order to attain an optimal description of eggplant drying. Applying ultrasound sped up the drying kinetics. The ultrasonic power was identified as having a significant (p<0.05) influence on both the effective moisture diffusivity and the mass transfer coefficient, which was well explained by linear relationships. The most complex model, which considered both external resistance and shrinkage to be significant phenomena, provided the best agreement with experimental data, giving percentages of explained variance of over 99.9% and mean relative errors of under 1.2% in every case. According to these results, ultrasound technology could have the potential to improve the convective drying of eggplant at an industrial scale. © 2011 Taylor & Francis Group, LLC.García Pérez, JV.; Ozuna López, C.; Ortuño Cases, C.; Carcel Carrión, JA.; Mulet Pons, A. (2011). Modeling Ultrasonically Assisted Convective Drying of Eggplan. Drying Technology. 29(13):1499-1509. doi:10.1080/07373937.2011.576321S149915092913Mujumdar, A. S. (2006). An overview of innovation in industrial drying: current status and R&D needs. Transport in Porous Media, 66(1-2), 3-18. doi:10.1007/s11242-006-9018-yChou, S. K., & Chua, K. J. (2001). New hybrid drying technologies for heat sensitive foodstuffs. 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Physics Procedia, 3(1), 35-47. doi:10.1016/j.phpro.2010.01.006De la Fuente-Blanco, S., Riera-Franco de Sarabia, E., Acosta-Aparicio, V. M., Blanco-Blanco, A., & Gallego-Juárez, J. A. (2006). Food drying process by power ultrasound. Ultrasonics, 44, e523-e527. doi:10.1016/j.ultras.2006.05.181García-Pérez, J. V., Cárcel, J. A., Riera, E., & Mulet, A. (2009). Influence of the Applied Acoustic Energy on the Drying of Carrots and Lemon Peel. Drying Technology, 27(2), 281-287. doi:10.1080/07373930802606428García-Pérez, J. V., Cárcel, J. A., Clemente, G., & Mulet, A. (2008). Water sorption isotherms for lemon peel at different temperatures and isosteric heats. LWT - Food Science and Technology, 41(1), 18-25. doi:10.1016/j.lwt.2007.02.010Mulet, A. (1994). Drying modelling and water diffusivity in carrots and potatoes. Journal of Food Engineering, 22(1-4), 329-348. doi:10.1016/0260-8774(94)90038-8Cunha, L. M., Oliveira, F. A. R., & Oliveira, J. C. (1998). Optimal experimental design for estimating the kinetic parameters of processes described by the Weibull probability distribution function. Journal of Food Engineering, 37(2), 175-191. doi:10.1016/s0260-8774(98)00085-5Azzouz, S., Guizani, A., Jomaa, W., & Belghith, A. (2002). Moisture diffusivity and drying kinetic equation of convective drying of grapes. Journal of Food Engineering, 55(4), 323-330. doi:10.1016/s0260-8774(02)00109-7Simal, S., Femenia, A., Garau, M. C., & Rosselló, C. (2005). Use of exponential, Page’s and diffusional models to simulate the drying kinetics of kiwi fruit. Journal of Food Engineering, 66(3), 323-328. doi:10.1016/j.jfoodeng.2004.03.025Maroulis, Z. B., Saravacos, G. D., Panagiotou, N. M., & Krokida, M. K. (2001). MOISTURE DIFFUSIVITY DATA COMPILATION FOR FOODSTUFFS: EFFECT OF MATERIAL MOISTURE CONTENT AND TEMPERATURE. International Journal of Food Properties, 4(2), 225-237. doi:10.1081/jfp-100105189Simal, S., Femenia, A., Garcia-Pascual, P., & Rosselló, C. (2003). Simulation of the drying curves of a meat-based product: effect of the external resistance to mass transfer. Journal of Food Engineering, 58(2), 193-199. doi:10.1016/s0260-8774(02)00369-2Queiroz, M. R., & Nebra, S. A. (2001). Theoretical and experimental analysis of the drying kinetics of bananas. Journal of Food Engineering, 47(2), 127-132. doi:10.1016/s0260-8774(00)00108-4Hassini, L., Azzouz, S., Peczalski, R., & Belghith, A. (2007). Estimation of potato moisture diffusivity from convective drying kinetics with correction for shrinkage. Journal of Food Engineering, 79(1), 47-56. doi:10.1016/j.jfoodeng.2006.01.025Hernández, J. A., Pavón, G., & Garcı́a, M. A. (2000). Analytical solution of mass transfer equation considering shrinkage for modeling food-drying kinetics. Journal of Food Engineering, 45(1), 1-10. doi:10.1016/s0260-8774(00)00033-9Souma, S., Tagawa, A., & Iimoto, M. (2004). Structural Properties for Fruits and Vegetables during Drying. NIPPON SHOKUHIN KAGAKU KOGAKU KAISHI, 51(11), 577-584. doi:10.3136/nskkk.51.577García-Pérez, J. V., Cárcel, J. A., de la Fuente-Blanco, S., & Riera-Franco de Sarabia, E. (2006). Ultrasonic drying of foodstuff in a fluidized bed: Parametric study. Ultrasonics, 44, e539-e543. doi:10.1016/j.ultras.2006.06.059Cárcel, J. A., García-Pérez, J. V., Riera, E., & Mulet, A. (2007). Influence of High-Intensity Ultrasound on Drying Kinetics of Persimmon. Drying Technology, 25(1), 185-193. doi:10.1080/07373930601161070Blasco, M., García-Pérez, J. V., Bon, J., Carreres, J. E., & Mulet, A. (2006). Effect of Blanching and Air Flow Rate on Turmeric Drying. Food Science and Technology International, 12(4), 315-323. doi:10.1177/1082013206067352Garau, M. C., Simal, S., Femenia, A., & Rosselló, C. (2006). Drying of orange skin: drying kinetics modelling and functional properties. Journal of Food Engineering, 75(2), 288-295. doi:10.1016/j.jfoodeng.2005.04.017Wu, L., Orikasa, T., Ogawa, Y., & Tagawa, A. (2007). Vacuum drying characteristics of eggplants. Journal of Food Engineering, 83(3), 422-429. doi:10.1016/j.jfoodeng.2007.03.030Chaves , M. ; Sgroppo , S.C. ; Avanza , J.R. Cinéticas de secado de berenjena (Solanum melongenaL.). Comunicaciones Científicas y Tecnológicas (Universidad Nacional del Nordeste Corrientes Argentina),2003,Resumen E-060 .Akpinar, E. K., & Bicer, Y. (2005). Modelling of the drying of eggplants in thin-layers. International Journal of Food Science and Technology, 40(3), 273-281. doi:10.1111/j.1365-2621.2004.00886.xDe Lima, A. (2002). Simultaneous moisture transport and shrinkage during drying of solids with ellipsoidal configuration. Chemical Engineering Journal, 86(1-2), 85-93. doi:10.1016/s1385-8947(01)00276-5RAHMAN, N., & KUMAR, S. (2007). INFLUENCE OF SAMPLE SIZE AND SHAPE ON TRANSPORT PARAMETERS DURING DRYING OF SHRINKING BODIES. Journal of Food Process Engineering, 30(2), 186-203. doi:10.1111/j.1745-4530.2007.00104.

Microenvironmental cooperation promotes early spread and bistability of a Warburg-like phenotype

We introduce an in silico model for the initial spread of an aberrant phenotype with Warburg-like overflow metabolism within a healthy homeostatic tissue in contact with a nutrient reservoir (the blood), aimed at characterizing the role of the microenvironment for aberrant growth. Accounting for cellular metabolic activity, competition for nutrients, spatial diffusion and their feedbacks on aberrant replication and death rates, we obtain a phase portrait where distinct asymptotic whole-tissue states are found upon varying the tissue-blood turnover rate and the level of blood-borne primary nutrient. Over a broad range of parameters, the spreading dynamics is bistable as random fluctuations can impact the final state of the tissue. Such a behaviour turns out to be linked to the re-cycling of overflow products by non-aberrant cells. Quantitative insight on the overall emerging picture is provided by a spatially homogeneous version of the model