359 research outputs found

    A minimal HIV-AIDS infection model with general incidence rate and application to Morocco data

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    We study the global dynamics of a SICA infection model with general incidence rate. The proposed model is calibrated with cumulative cases of infection by HIV-AIDS in Morocco from 1986 to 2015. We first prove that our model is biologically and mathematically well-posed. Stability analysis of different steady states is performed and threshold parameters are identified where the model exhibits clearance of infection or maintenance of a chronic infection. Furthermore, we examine the robustness of the model to some parameter values by examining the sensitivity of the basic reproduction number. Finally, using numerical simulations with real data from Morocco, we show that the model predicts well such reality.Comment: This is a preprint of a paper whose final and definite form is with 'Statistics Opt. Inform. Comput.', Vol. 7, No 2 (2019). See [http://www.IAPress.org]. Submitted 16/Sept/2018; Revised 10 & 15/Dec/2018; Accepted 15/Dec/201

    The power fractional calculus: first definitions and properties with applications to power fractional differential equations

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    Using the Laplace transform method and the convolution theorem, we introduce new and more general definitions for fractional operators with non-singular kernels, extending well-known concepts existing in the literature. The new operators are based on a generalization of the Mittag–Leffler function, characterized by the presence of a key parameter p. This power parameter p is important to enable researchers to choose an adequate notion of the derivative that properly represents the reality under study, to provide good mathematical models, and to predict future dynamic behaviors. The fundamental properties of the new operators are investigated and rigorously proved. As an application, we solve a Caputo and a Riemann–Liouville fractional differential equation.Fundação para a Ciência e a Tecnologia (FCT), grant number UIDB/04106/2020 (CIDMA).publishe

    Weighted Generalized Fractional Integration by Parts and the Euler-Lagrange Equation

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    Integration by parts plays a crucial role in mathematical analysis, e.g., during the proof of necessary optimality conditions in the calculus of variations and optimal control. Motivated by this fact, we construct a new, right-weighted generalized fractional derivative in the Riemann-Liouville sense with its associated integral for the recently introduced weighted generalized fractional derivative with Mittag-Leffler kernel. We rewrite these operators equivalently in effective series, proving some interesting properties relating to the left and the right fractional operators. These results permit us to obtain the corresponding integration by parts formula. With the new general formula, we obtain an appropriate weighted Euler-Lagrange equation for dynamic optimization, extending those existing in the literature. We end with the application of an optimization variational problem to the quantum mechanics framework.Comment: This is a preprint of a paper whose final and definite form is published Open Access in 'Axioms' at [https://doi.org/10.3390/axioms11040178

    Evaluating the Effects of Environmental Conditions on Sensed Parameters for Green Areas Monitoring and Smart Irrigation Systems

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    [EN] The irrigation of green areas in cities should be managed appropriately to ensure its sustainability. In large cities, not all green areas might be monitored simultaneously, and the data acquisition time can skew the gathered value. Our purpose is to evaluate which parameter has a lower hourly variation. We included soil parameters (soil temperature and moisture) and plant parameters (canopy temperature and vegetation indexes). Data were gathered at 5 different hours in 11 different experimental plots with variable irrigation and with different grass composition. The results indicate that soil moisture and Normalized Difference Vegetation Index are the sole parameters not affected by the data acquisition time. For soil moisture, the maximum difference was in experimental plot 4, with values of 21% at 10:45 AM and 27% at 8:45 AM. On the other hand, canopy temperature is the most affected parameter with a mean variation of 15 degrees C in the morning. The maximum variation was in experimental plot 8 with a 19 degrees C at 8:45 AM and 39 degrees C at 12:45 PM. Data acquisition time affected the correlation between soil moisture and canopy temperature. We can affirm that data acquisition time has to be included as a variability source. Finally, our conclusion indicates that it is vital to consider data acquisition time to ensure water distribution for irrigation in cities.This research was funded by AREA VERDE-MG projects, by project PDR18-XEROCESPED funded under the PDR-CM 2014-2020 by the EU (European Agricultural Fund for Rural Development, EAFRD), Spanish Ministry of Agriculture, Fisheries and Food (MAPA) and Comunidad de Madrid regional government through IMIDRA, and by the Conselleria de Educacion, Cultura y Deporte through "Subvenciones para la contratacion de personal investigador en fase postdoctoral", grant number APOSTD/2019/04.Mauri Ablanque, PV.; Parra-Boronat, L.; Yousfi, S.; Lloret, J.; Marin, JF. (2021). Evaluating the Effects of Environmental Conditions on Sensed Parameters for Green Areas Monitoring and Smart Irrigation Systems. Sensors. 21(6):1-22. https://doi.org/10.3390/s2106225512221

    Modeling and forecasting of COVID-19 spreading by delayed stochastic differential equations

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    The novel coronavirus disease (COVID-19) pneumonia has posed a great threat to the world recent months by causing many deaths and enormous economic damage worldwide. The first case of COVID-19 in Morocco was reported on 2 March 2020, and the number of reported cases has increased day by day. In this work, we extend the well-known SIR compartmental model to deterministic and stochastic time-delayed models in order to predict the epidemiological trend of COVID-19 in Morocco and to assess the potential role of multiple preventive measures and strategies imposed by Moroccan authorities. The main features of the work include the well-posedness of the models and conditions under which the COVID-19 may become extinct or persist in the population. Parameter values have been estimated from real data and numerical simulations are presented for forecasting the COVID-19 spreading as well as verification of theoretical results.publishe

    Drone RGB Images as a Reliable Information Source to Determine Legumes Establishment Success

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    [EN] The use of drones in agriculture is becoming a valuable tool for crop monitoring. There are some critical moments for crop success; the establishment is one of those. In this paper, we present an initial approximation of a methodology that uses RGB images gathered from drones to evaluate the establishment success in legumes based on matrixes operations. Our aim is to provide a method that can be implemented in low-cost nodes with relatively low computational capacity. An index (B1/B2) is used for estimating the percentage of green biomass to evaluate the establishment success. In the study, we include three zones with different establishment success (high, regular, and low) and two species (chickpea and lentils). We evaluate data usability after applying aggregation techniques, which reduces the picture's size to improve long-term storage. We test cell sizes from 1 to 10 pixels. This technique is tested with images gathered in production fields with intercropping at 4, 8, and 12 m relative height to find the optimal aggregation for each flying height. Our results indicate that images captured at 4 m with a cell size of 5, at 8 m with a cell size of 3, and 12 m without aggregation can be used to determine the establishment success. Comparing the storage requirements, the combination that minimises the data size while maintaining its usability is the image at 8 m with a cell size of 3. Finally, we show the use of generated information with an artificial neural network to classify the data. The dataset was split into a training dataset and a verification dataset. The classification of the verification dataset offered 83% of the cases as well classified. The proposed tool can be used in the future to compare the establishment success of different legume varieties or species.This research and the contract of S.Y. were funded by project PDR18-XEROCESPED, under the PDR-CM 2014-2020, by the EU (European Agricultural Fund for Rural Development, EAFRD), Spanish Ministry of Agriculture, Fisheries and Food (MAPA) and Comunidad de Madrid regional government through IMIDRA and the contract of L.P. was funded by Conselleria de Educacion, Cultura y Deporte with the Subvenciones para la contratacion de personal investigador en fase postdoctoral, APOSTD/2019/04.Parra-Boronat, L.; Mostaza-Colado, D.; Yousfi, S.; Marin, JF.; Mauri, PV.; Lloret, J. (2021). Drone RGB Images as a Reliable Information Source to Determine Legumes Establishment Success. Drones. 5(3):1-18. https://doi.org/10.3390/drones5030079S1185

    Sandy contourite drift in the late Miocene Rifian Corridor (Morocco):Reconstruction of depositional environments in a foreland-basin seaway

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    The Rifian Corridor was a seaway between the Atlantic Ocean and the Mediterranean Sea during the late Miocene. The seaway progressively closed, leading to the Messinian Salinity Crisis in the Mediterranean Sea. Despite the key palaeogeographic importance of the Rifian Corridor, patterns of sediment transport within the seaway have not been thoroughly studied. In this study, we investigated the upper Miocene sedimentation and bottom current pathways in the South Rifian Corridor. The planktic and benthic foraminifera of the upper Tortonian and lower Messinian successions allow us to constrain the age and palaeo-environment of deposition. Encased in silty marls deposited at 150–300 m depth, there are (i) 5 to 50 m thick, mainly clastic sandstone bodies with unidirectional cross-bedding; and (ii) 50 cm thick, mainly clastic, tabular sandstone beds with bioturbation, mottled silt, lack of clear base or top, and bi-gradational sequences. Furthermore, seismic facies representing elongated mounded drifts and associated moat are present at the western mouth of the seaway. We interpret these facies as contourites: the products of a westward sedimentary drift in the South Rifian Corridor. The contourites are found only on the northern margin of the seaway, thus suggesting a geostrophic current flowing westward along slope and then northward. This geostrophic current may have been modulated by tides. By comparing these fossil examples with the modern Gulf of Cadiz, we interpret these current-dominated deposits as evidence of late Miocene Mediterranean overflow into the Atlantic Ocean, through the Rifian Corridor. This overflow may have affected late Miocene ocean circulation and climate, and the overflow deposits may represent one of the first examples of mainly clastic contourites exposed on land

    Brushing RemInder 4 Good oral HealTh (BRIGHT) trial: does an SMS behaviour change programme with a classroom-based session improve the oral health of young people living in deprived areas? A study protocol of a randomised controlled trial

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    Background: Almost one-half of 12–15 year olds living in deprived areas of the UK have dental caries (tooth decay) with few oral health promotion programmes aimed at children of this age. Mobile phone-based interventions such as short messaging service (SMS) interventions have been found effective at changing certain behaviours and improving health outcomes. This protocol describes the BRIGHT Trial, investigating the clinical and cost-effectiveness of a behaviour change intervention—classroom-based session (CBS) embedded in the curriculum and a series of SMS delivered to participants twice daily to remind them to brush their teeth, compared to usual curriculum and no SMS—to reduce the prevalence of dental caries in young people from deprived areas. Objectives: To investigate the clinical and cost-effectiveness of a complex intervention to improve the oral health of young people living in deprived areas. Methods/design: This is a school-based, assessor-blinded, two-arm cluster-randomised controlled trial with an internal pilot trial. Overall, the trial will involve approximately 5040 11–13 year olds in 42 schools with a 3-year follow-up. The trial will take place in secondary schools in England, Scotland and Wales. The primary outcome is the presence of carious lesions in permanent teeth at 3 years. Secondary outcomes are: number of carious teeth, frequency of twice-daily toothbrushing, plaque levels, gingivitis, child health-related quality of life and oral health-related quality of life. A cost-utility analysis will be conducted. Discussion: The findings of the trial have implications for embedding oral health interventions into school curricula guidance produced by national bodies, including departments for education and dental public health and guideline-development organisations. Trial registration: ISRCTN registry, ISRCTN12139369. Registered on 10 May 2017

    The oral health of secondary school pupils:baseline data from the Brushing RemInder 4 Good oral HealTh (BRIGHT) trial

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    Background This paper describes the sociodemographics and oral health of UK secondary school pupils. They were participants of the BRIGHT trial, which was designed to evaluate the effectiveness of a toothbrushing intervention to reduce dental caries. Methods Overall, 4,680 pupils aged 11-13 years attending 42 secondary schools in England, Scotland and Wales with above average proportion of pupils eligible for free school meals, were recruited to the trial. Sociodemographic data were collected. Participants had a clinical assessment for caries, plaque and bleeding and completed measures of oral and general health-related quality of life and oral health behaviours (frequency of toothbrushing, dental attendance and cariogenic food/drinks consumed). Regression analyses were performed. Results Over one-third (34.7%) of participants had caries experience, with 44.5% reporting their oral health had an impact on their daily lives. Factors associated with a statistically significant increased likelihood of caries experience were older age, being female, eligibility for free school meals, worse oral health-related quality of life, higher cariogenic diet, less than twice-daily toothbrushing, living in a more deprived area and lower school attendance. Conclusions The prevalence and impact of dental caries on the lives of pupils remains high, with further oral health promotion activities needed in targeted secondary schools.</p
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