46 research outputs found

    Computational modelling with uncertainty of frequent users of e-commerce in Spain using an age-group dynamic nonlinear model with varying size population

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    [EN] Electronic commerce (EC) has numerous advantages. It allows saving time when we purchase an item, offers the possibility of review without depending on the schedules of traditional stores, access to a wider variety and quantity of articles, in many cases, with lower prices, etc. Based upon mathematical epidemiology tenets strongly related to social behavior able to describe the influence of peers, in this paper we propose an age-group dynamic model with population varying size based on a system of difference equations to study the evolution of the frequent users of EC over time in Spain. Using data from surveys retrieved from the Spanish National Statistics Institute, we use and design computational algorithms to perform a probabilistic estimation of the model parameters that allow the model output to capture the data uncertainty. Then, we will be able to perform a precise prediction with uncertainty.This work has been partially supported by the Ministerio de Economia y Competitividad grant MTM2017-89664-P and by the European Union through the Operational Program of the European Regional Development Fund (ERDF)/European Social Fund (ESF) of the Valencian Community 2014-2020, grants GJIDI/2018/A/009 and GJIDI/2018/A/010.Burgos-Simon, C.; Cortés, J.; Martínez-Rodríguez, D.; Villanueva Micó, RJ. (2019). Computational modelling with uncertainty of frequent users of e-commerce in Spain using an age-group dynamic nonlinear model with varying size population. Advances in Complex Systems. 22(4):1950009-1-1950009-17. https://doi.org/10.1142/S0219525919500097S1950009-11950009-17224Bettencourt, L. (1997). Customer voluntary performance: Customers as partners in service delivery. Journal of Retailing, 73(3), 383-406. doi:10.1016/s0022-4359(97)90024-5Brauer, F., & Castillo-Chávez, C. (2001). Mathematical Models in Population Biology and Epidemiology. Texts in Applied Mathematics. doi:10.1007/978-1-4757-3516-1Cortés, J.-C., Lombana, I.-C., & Villanueva, R.-J. (2010). Age-structured mathematical modeling approach to short-term diffusion of electronic commerce in Spain. Mathematical and Computer Modelling, 52(7-8), 1045-1051. doi:10.1016/j.mcm.2010.02.030Hethcote, H. W. (2000). The Mathematics of Infectious Diseases. SIAM Review, 42(4), 599-653. doi:10.1137/s0036144500371907Yanhui, L., & Siming, Z. (2007). Competitive dynamics of e-commerce web sites. Applied Mathematical Modelling, 31(5), 912-919. doi:10.1016/j.apm.2006.03.029Mahajan, V., Muller, E., & Bass, F. M. (1991). New Product Diffusion Models in Marketing: A Review and Directions for Research. Diffusion of Technologies and Social Behavior, 125-177. doi:10.1007/978-3-662-02700-4_6Turban, E., Outland, J., King, D., Lee, J. K., Liang, T.-P., & Turban, D. C. (2018). Electronic Commerce 2018. Springer Texts in Business and Economics. doi:10.1007/978-3-319-58715-

    Mathematical modeling of the dynamics of the bladder cancer and the immune response applied to a patient: Evolution and short-term prediction

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    [EN] Bladder cancer is one of the most common malignant diseases in the urinary system and a highly aggressive neoplasm. The prognosis is not favorable usually, and its evolution for particular patients is very difficult to find out. In this paper, we propose a dynamic mathematical model that describes the bladder tumor growth and the immune response evolution. This model is customized for a single patient, determining appropriate model parameter values via model calibration. Due to the uncertainty of the tumor evolution, using the calibrated model parameters, we predict the tumor size and the immune response evolution over the next few months assuming three different scenarios: favorable, neutral, and unfavorable. In the former, it is not expected any trace of the cancer in the middle of September 2018 (after 16 mo). In the neutral scenario, at the same date, a 7- to 8-mm tumor is expected. In the worst case, a 40-mm tumor is expected. The patient was cited on 10 September 2018 to check the tumor size, and according to the doctors, there was no sign of recurrence. It seems that we are in the favorable scenario. The patient will be called again for follow-up in mid-2019.This work has been supported by the Ministerio de Economía, Industria y Competitividad grant MTM2017-89664-P.Burgos-Simon, C.; García-Medina, N.; Martínez-Rodríguez, D.; Villanueva Micó, RJ. (2019). Mathematical modeling of the dynamics of the bladder cancer and the immune response applied to a patient: Evolution and short-term prediction. Mathematical Methods in the Applied Sciences. 42(17):5746-5757. https://doi.org/10.1002/mma.5536S574657574217Official Site for Spanish Medic Oncology Society.https://www.seom.org. Accessed: 25/09/2018.Greenlee, R. T., Hill-Harmon, M. B., Murray, T., & Thun, M. (2001). Cancer Statistics, 2001. CA: A Cancer Journal for Clinicians, 51(1), 15-36. doi:10.3322/canjclin.51.1.15Holmang, S., Hedelin, H., Anderstrom, C., & Johansson, S. L. (1995). The Relationship Among Multiple Recurrences, Progression and Prognosis of Patients with Stages TA and T1 Transitional Cell Cancer of the Bladder Followed for at least 20 years. Journal of Urology, 153(6), 1823-1827. doi:10.1016/s0022-5347(01)67321-xRedelman-Sidi, G., Glickman, M. S., & Bochner, B. H. (2014). The mechanism of action of BCG therapy for bladder cancer—a current perspective. Nature Reviews Urology, 11(3), 153-162. doi:10.1038/nrurol.2014.15Bladder Cancer Treatment (PDQ)‐Health Professional Version.https://www.cancer.gov/types/bladder/hp/bladder-treatment-pdq. Accessed: 25/09/2018.Bladder Cancer Treatment (PDQ)‐Patient Version.https://www.cancer.gov/types/bladder/patient/bladder-treatment-pdq. Accessed: 25/09/2018.Official Site for Hospital Universitari i Politècnic La Fe Valencia Spain.http://www.hospital-lafe.com. Accessed: 25/09/2018.Hanahan, D., & Weinberg, R. A. (2011). Hallmarks of Cancer: The Next Generation. Cell, 144(5), 646-674. doi:10.1016/j.cell.2011.02.013Dong, H., Strome, S. E., Salomao, D. R., Tamura, H., Hirano, F., Flies, D. B., … Chen, L. (2002). Tumor-associated B7-H1 promotes T-cell apoptosis: A potential mechanism of immune evasion. Nature Medicine, 8(8), 793-800. doi:10.1038/nm730Fernandez, N. C., Lozier, A., Flament, C., Ricciardi-Castagnoli, P., Bellet, D., Suter, M., … Zitvogel, L. (1999). Dendritic cells directly trigger NK cell functions: Cross-talk relevant in innate anti-tumor immune responses in vivo. Nature Medicine, 5(4), 405-411. doi:10.1038/7403Factsheet of OncoTICE 2 − 8 × 108UFC powder for suspension intravesical (in Spanish).https://www.aemps.gob.es/cima/pdfs/es/ft/61377/61377_ft.pdf. Accessed: 25/09/2018

    Blocking human fear memory with the matrix metalloproteinase inhibitor doxycycline

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    Learning to predict threat is a fundamental ability of many biological organisms, and a laboratory model for anxiety disorders. Interfering with such memories in humans would be of high clinical relevance. On the basis of studies in cell cultures and slice preparations, it is hypothesised that synaptic remodelling required for threat learning involves the extracellular enzyme matrix metalloproteinase (MMP) 9. However, in vivo evidence for this proposal is lacking. Here we investigate human Pavlovian fear conditioning under the blood-brain barrier crossing MMP inhibitor doxycyline in a pre-registered, randomised, double-blind, placebo-controlled trial. We find that recall of threat memory, measured with fear-potentiated startle 7 days after acquisition, is attenuated by ~60% in individuals who were under doxycycline during acquisition. This threat memory impairment is also reflected in increased behavioural surprise signals to the conditioned stimulus during subsequent re-learning, and already late during initial acquisition. Our findings support an emerging view that extracellular signalling pathways are crucially required for threat memory formation. Furthermore, they suggest novel pharmacological methods for primary prevention and treatment of posttraumatic stress disorder.Molecular Psychiatry advance online publication, 4 April 2017; doi:10.1038/mp.2017.65

    Haemodynamic effects of the nitroxyl donor cimlanod (BMS-986231) in chronic heart failure: a randomized trial

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    Aims Nitroxyl provokes vasodilatation and inotropic and lusitropic effects in animals via post-translational modification of thiols. We aimed to compare effects of the nitroxyl donor cimlanod (BMS-986231) with those of nitroglycerin (NTG) or placebo on cardiac function in patients with chronic heart failure with reduced ejection fraction (HFrEF). Methods and results In a randomized, multicentre, double-blind, crossover trial, 45 patients with stable HFrEF were given a 5 h intravenous infusion of cimlanod, NTG, or placebo on separate days. Echocardiograms were done at the start and end of each infusion period and read in a core laboratory. The primary endpoint was stroke volume index derived from the left ventricular outflow tract at the end of each infusion period. Stroke volume index with placebo was 30 ± 7 mL/m2 and was lower with cimlanod (29 ± 9 mL/m2; P = 0.03) and NTG (28 ± 8 mL/m2; P = 0.02). Transmitral E-wave Doppler velocity on cimlanod or NTG was lower than on placebo and, consequently, E/e′ (P = 0.006) and E/A ratio (P = 0.003) were also lower. NTG had similar effects to cimlanod on these measurements. Blood pressure reduction was similar with cimlanod and NTG and greater than with placebo. Conclusion In patients with chronic HFrEF, the haemodynamic effects of cimlanod and NTG are similar. The effects of cimlanod may be explained by venodilatation and preload reduction without additional inotropic or lusitropic effects. Ongoing trials of cimlanod will further define its potential role in the treatment of heart failure

    Imitation in one’s own presence: no specific effect of self-focus on imitation

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    Previous studies have reported that imitative responses may be modulated by top-down social factors such as self-focus. However, growing evidence suggests that such social factors may actually modulate domain-general processes such as spatially compatible responding, rather than specifically social processes such as imitation. In this study, we aimed to identify the cognitive processes being modulated under conditions of heightened or diminished self-focus. Participants performed a stimulus-response compatibility task which independently measures both spatial and imitative response tendencies, under two conditions: heightened self-focus, where the task was performed in the presence of two mirrors; and diminished self-focus, where the mirrors were covered. While participants were faster to respond to compatible trials than to incompatible trials, both imitatively and spatially, there was no significant modulation of either spatial or imitative compatibility by self-focus; although the magnitude of the modulation of spatial compatibility was numerically similar to the effect of self-focus on imitation found in previous studies. These results provide no evidence for an effect of self-focus on either socialspecific, or domain-general, processes

    Unlocking the potential of nanobiohybrids to combat environmental pollution

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    The destructive effects of the world's population growth, which have led to the overuse of primary resources, are evident today. Recently, the world has hit an 8 billion population mark, which is accompanied by an increase in waste generation. Anthropogenic activities lead to environmental pollution that is a problem of great importance, and it is essential to develop economically sound, eco-friendly, and sustainable technologies to tackle this ever-increasing problem of the 21st century. Innovations are required since they can contribute to the creation of sophisticated, sustainable, and novel goods for ecological repair. Such properties can be seen in the current advancements of nanotechnologies and new performing nanomaterials. They have a substantial surface area, enzymatic activity, and responsiveness and are easily functionalized to chemically modify their characteristics. This chapter examines current advancements in bioremediation methods used in conjunction with various nanocomposites and nanobiohybrids to recover the environment from pollution. Special focus is placed on environmentally friendly and regenerative nanosolutions, as well as their secure properties

    Sensitivity analysis of time dependent settlements in hydraulic fills

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    This paper reports some numerical investigation carried out on hydraulic fills. A methodology based on the numerical solution of the governing equation via the finite volume method is introduced and tested, and proven to be very efficient. Typical dimensional performance curves are obtained and the influence of governing parameters is discussed. A sensitivity analysis is carried out in order to characterize the influence of the numerous parameters used to simulate the time dependent settlement in hydraulic fills on the outputs of the model
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