A Comparative Predicting Stock Prices using Heston and Geometric Brownian Motion Models

This paper presents a novel approach to predicting stock prices using technical analysis. By utilizing Ito's lemma and Euler-Maruyama methods, the researchers develop Heston and Geometric Brownian Motion models that take into account volatility, interest rate, and historical stock prices to generate predictions. The results of the study demonstrate that these models are effective in accurately predicting stock prices and outperform commonly used statistical indicators. The authors conclude that this technical analysis-based method offers a promising solution for stock market prediction

The effects of drought stress and type of fertiliser on generalist and specialist herbivores and their natural enemies

Abiotic stresses such as drought and nutrient availability can affect invertebrate herbivores feeding on plants, and potentially cascade up to impact their predators and parasitoids. Although these two factors separately been the subject of many studies, there are few tests of their combined effects in the context of pest species and their natural enemies on cultivated plants. Climate change models predict an increase in the frequency and severity of droughts, while the type and amount of fertiliser applied to crops is more under the control of growers. Understanding how these two abiotic factors may interact is key to utilising the potential of natural enemies to control pests under a future climate. To address this, a range of drought and fertiliser type treatments were applied to a model Brassica system in a factorial design, and the performance of two ubiquitous aphid species and their parasitoids was assessed. One aphid species was a specialist on Brassicas (Brevicoryne brassicae, with parasitoid Diaeretiella rapae) and the second a generalist aphid species (Myzus persicae, with parasitoid Aphidius colemani). The performance of both aphid species responded in a similar way to the treatments, and was maximised on plants growing in organic fertilisers under medium levels of drought stress. The strongest effects of drought and fertiliser cascaded up to affect parasitoids. Parasitoid performance responded in a broadly similar way to their aphid host performance in relation to fertiliser type. Some of the smaller effects of fertiliser treatments on aphid performance were not found for parasitoid performance. Aphid performance was greatest on plants under medium drought stress, but the parasitoids only responded consistently to the high drought stress treatment, on which their performance was reduced. Interactions between the drought and fertiliser did not have a large effect on aphid or parasitoid performance, compared with the strong main effects found for each treatment. These results are discussed in the context of previous and future research on the impacts of abiotic stresses on invertebrate herbivores and their natural enemies

Numerical Study for MHD Stagnation-Point Flow of a Micropolar Nanofluid Towards a Stretching Sheet

In this paper, we investigated the magnetohydrodynamic (MHD) stagnation-point flow of micropolar nanofluid over a stretching sheet. A uniform magnetic field is applied normal to the flow. Nonlinear micropolar nanofluid problem in the presence of the strong concentration of microelements is modeled and then solved by numerical techniques. A parametric study of the involved parameters in the presence of spin gradient viscosity is conducted, and representative set of numerical results is illustrated in the graphical and tabular forms. The complete formulation of the Keller-box method for the considered flow problem is given, and a comparison of the obtained results is performed with the previous published results. The comparison shows that our present results have an excellent match with the previous results in a limiting case. We found that the non-dimensional temperature and its associated thermal boundary layer thickness are enhanced when we use the larger values of thermophoresis and Brownian motion parameter. The non-dimensional concentration is higher for larger thermophoresis parameter but smaller for higher Brownian motion parameter. It is also observed that the smaller values of Lewis number correspond to higher non-dimensional concentration and its associated boundary layer thickness

Sustainable and Resilient Smart Water Grids: A Solution for Developing Countries

According to a United Nations report, the world population will increase from 7 billion to 9 billion by 2050. Further, the water stress level is more than 70% in 22 countries while in another 31 countries it is between 25% and 70%. More than 2 billion people live in these 53 countries which are all underdeveloped. Water use has increased by 1% per year since the 1980s, so global demand is expected to rise by 30% by 2050. Thus, efficient water grid management is imperative to ensure there is sufficient water for the future. Information and Communication Technology (ICT) can be used to create smart water grids to optimize water distribution, reduce waste and leakage, and resolve quality and overuse issues. In this work, a low cost, real-time, reliable and sustainable IoT based solution called SmartTubewell is proposed for smart water grid management. It is composed of two components, a sensor node installed at tube wells and an application layer on Amazon Web Services (AWS) for data analysis, storage and processing. The sensor node is based on a Raspberry Pi with integrated current and voltage sensors and a local database. The sensor data is transmitted to AWS using a cellular (GPRS) network. A comparison between the proposed system and SCADA is presented which shows that SmartTubewell has a much lower cost. A field test with multiple tube wells in Peshawar, Pakistan indicates that this is a suitable solution for developing countries

Graphene oxide as an efficient photocatalyst for photocatalytic reduction of CO2 into solar fuel

Photocatalytic reduction of CO2 into solar fuel such as methane and methanol, is an attractive approach to simultaneously solve the energy crisis and global warming problem. Herein, comparative photocatalytic activity of graphene oxide nanosheets have been investigated for photocatalytic reduction of CO2 into methane and methanol in continuous gas and liquid phase photoreactor system. The graphene oxide sheets were prepared according to Tour's method. The chemical composition and optical properties was evaluated through XPS and UV-vis spectroscopy. Graphene oxide nanosheets exhibited maximum amount of 224.87 μmol/g.h methanol and 14.8 μmol/g.h methane in liquid and gas phase system, respectively. Higher yield of methanol in liquid phase compared to methane in gaseous system can be attributed to dispersion of graphene oxide sheets in water. Hence, graphene oxide nanosheets are efficient photocatalyst for CO2 reduction into methanol. Nevertheless, further research is essential to improve the photostability of graphene oxide sheets for real application of photocatalytic CO2 reduction

Flow of Power-Law Nanofluid over a Stretching Surface with Newtonian Heating

The present investigation addresses the effect of Newtonian heating in the laminar flow of power law nanofluid. The flow is induced by a stretching surface. The nonlinear analysis comprising flow and energy equations is computed. The problems are solved for the series solutions of velocity and temperature. Skin friction coefficient and Nusselt number are computed. A parametric study is performed for the influential parameters on the velocity and temperature. Physical interpretation of the derived solutions is presented

Flow and Heat Transfer over an Unsteady Stretching Sheet in a Micropolar Fluid with Convective Boundary Condition

This article is concerned with the flow of micropolar fluid over an unsteady stretching surface with convective boundary condition. The governing partial differential equations are first converted into ordinary differential equations using appropriate transformations and then solved for the series solutions. Influence of micropolar parameter, unsteadiness parameter, boundary parameter, Prandtl number and Biot number on the flow and heat transfer characteristics is examined. Numerical values of local Nusselt number and skin friction coefficient are presented and analyzed. It is observed that temperature is an increasing function of Biot number

Stagnation Point Flow of Thixotropic Fluid over a Stretching Sheet with Mass Transfer and Chemical Reaction

The stagnation point flow of thixotropic fluid towards a linear stretching surface is investigated. Mass transfer with first order chemical reaction is considered. The resulting partial differential equations are reduced into the ordinary differential equations. Dimensionless velocity and concentration fields have been computed. Graphical plots are presented to illustrate the details of flow and mass transfer characteristics and their dependence upon the physical parameters. Numerical values of surface mass transfer are first computed and then analyzed

Mixed Convection Flow of Casson Nanofluid over a Stretching Sheet with Convectively Heated Chemical Reaction and Heat Source/Sink

The present study addresses the mixed convection flow of non-Newtonian nanofluid over a stretching surface in presence of thermal radiation, heat source/sink and first order chemical reaction. Casson fluid model is adopted in the present study. Magnetic field contribution is incorporated in the momentum equation whereas the aspects of nanoparticles are considered in the energy and concentration equations. Convective boundary conditions for both heat and mass transfer are utilized. Similarity transformations are employed to reduce the partial differential equations into ordinary differential equations. Series solutions of the resulting problem are obtained. Impacts of all the physical parameters on the velocity, temperature and concentration fields are analyzed graphically. Numerical values of different involved parameters for local skin friction coefficient, local Nusselt and Sherwood numbers are obtained and discussed

Dysfunctional lens syndrome

Purpose: To report the pre- and post-operative findings of a case with dysfunctional lens syndrome. Methods: An adult patient was evaluated using iTrace aberrometer, Tomey topographer and slitlamp biomicroscopy to confirm dysfunctional lens syndrome. Results: A 45-year-old male patient presented with the chief complaint of poor visual quality; uncorrected visual acuity 20/40 in the right eye, best spectacle corrected visual acuity 20/25 in the right eye with refraction Plano/−1.50 × 80 (SE = −0.75D). Pre- and post-operative root-mean-square (RMS) of total higherorder aberrations in the entire eye, the internal optics and the cornea were 0.350 & 0.257, 0.311 & 0.236 and 0.214 & 0.191 micron (μ), respectively. Also, the magnitude of preoperative total, internal and corneal coma was 0.254 μ × 222°, 0.274μ×242° and 0.097μ × 131° and postoperative values were 0.170 μ × 162°, 0.131 μ × 177°, 0.054 μ × 125°, respectively. Conclusion: These results show that sometime the HOAs of the internal optics, mainly crystalline lens, are not compensated by the cornea and this may cause visual discomfort in the absence of any significant cataract, this situation is known as dysfunctional lens syndrome (DLS)