Search results for: variance reduction

Authors: Devendra Kumar Pandey, Debabrata Chakraborty

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The advancement in various concrete ingredients like plasticizers, additives and fibers, etc. has enabled concrete technologists to develop many viable varieties of special concretes in recent decades. Such various varieties of concrete have significant enhancement in green as well as hardened properties of concrete. A prudent selection of appropriate type of concrete can resolve many design and application issues in construction projects. This paper focuses on usage of self-compacting concrete, high early strength concrete, structural lightweight concrete, fiber reinforced concrete, high performance concrete and ultra-high strength concrete in the structures. The modified properties of strength at various ages, flowability, porosity, equilibrium density, flexural strength, elasticity, permeability etc. need to be carefully studied and incorporated into the design of the structures. The paper demonstrates various mixture combinations and the concrete properties that can be leveraged. The selection of such products based on the end use of structures has been proposed in order to efficiently utilize the modified characteristics of these concrete varieties. The study involves mapping the characteristics with benefits and savings for the structure from design perspective. Self-compacting concrete in the structure is characterized by high shuttering loads, better finish, and feasibility of closer reinforcement spacing. The structural design procedures can be modified to specify higher formwork strength, height of vertical members, cover reduction and increased ductility. The transverse reinforcement can be spaced at closer intervals compared to regular structural concrete. It allows structural lightweight concrete structures to be designed for reduced dead load, increased insulation properties. Member dimensions and steel requirement can be reduced proportionate to about 25 to 35 percent reduction in the dead load due to self-weight of concrete. Steel fiber reinforced concrete can be used to design grade slabs without primary reinforcement because of 70 to 100 percent higher tensile strength. The design procedures incorporate reduction in thickness and joint spacing. High performance concrete employs increase in the life of the structures by improvement in paste characteristics and durability by incorporating supplementary cementitious materials. Often, these are also designed for slower heat generation in the initial phase of hydration. The structural designer can incorporate the slow development of strength in the design and specify 56 or 90 days strength requirement. For designing high rise building structures, creep and elasticity properties of such concrete also need to be considered. Lastly, certain structures require a performance under loading conditions much earlier than final maturity of concrete. High early strength concrete has been designed to cater to a variety of usages at various ages as early as 8 to 12 hours. Therefore, an understanding of concrete performance specifications for special concrete is a definite door towards a superior structural design approach.

Keywords: high performance concrete, special concrete, structural design, structural lightweight concrete

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Authors: Abd Al-Salam Al-Masgari, Haylay Tsegab, Ismailalwali Babikir, Monera A. Shoieb

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We present a study of Malaysia's Central Luconia region, which is an essential deposit of Miocene carbonate reservoirs. This study aims to identify and map areas of selected carbonate platforms, develop high-resolution statistical karst models, and generate comprehensive karst geobody models for selected carbonate fields. This study uses seismic characterization and advanced geophysical surveys to identify karst signatures in Miocene carbonate reservoirs. The results highlight the use of variance, RMS, RGB colour blending, and 3D visualization Prop seismic sequence stratigraphy seismic attributes to visualize the karstified areas across the F23 field of Central Luconia. The offshore karst model serves as a powerful visualization tool to reveal the karstization of carbonate sediments of interest. The results of this study contribute to a better understanding of the karst distribution of Miocene carbonate reservoirs in Central Luconia, which are essential for hydrocarbon exploration and production. This is because these features significantly impact the reservoir geometry, flow path and characteristics.

Keywords: karst, central Luconia, seismic attributes, Miocene carbonate build-ups

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Authors: Mathias Twizeyimana, Urmila Adhikari, Julius P. Sserumaga, David Ingham

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The management of aflatoxins (naturally occurring toxins produced by certain fungi, most importantly Aspergillus flavus and A. parasiticus) relies mostly on the use of best cultural practices and, in some cases, the use of the biological control consisting of atoxigenic strains inhibiting the toxigenic strains through competition resulting in considerable toxin reduction. At AgBiome, we have built a core collection of over 100,000 fully sequenced microbes from diverse environments and employ both the microbes and their sequences in the discovery of new biological products for disease and pest control. The most common approach to finding beneficial microbes consists of isolating microorganisms from samples collected from diverse environments, selecting antagonistic strains through empirical screening, studying modes of action, and stabilization through the formulation of selected microbial isolates. A total of 608 diverse bacterial strains were screened using a high-throughput assay (48-well assay) to identify strains that inhibit toxigenic A. flavus growth on maize kernels. Active strains in 48-well assay had their pathogen inhibiting activity confirmed using the Flask Assay and were concurrently tested for their ability to reduce the aflatoxin content in maize grains. Strains with best growth inhibition and reduction of aflatoxin were tested in the greenhouse and field trials. From the field trials, three bacterial strains, AFS000009 (Pseudomonas chlororaphis), AFS032321 (Bacillus subtilis), AFS024683 (Bacillus velezensis), had aflatoxin concentrations (ppb) values that were significantly lower than those of inoculated control. The identification of biological products with high efficacy in inhibiting pathogen growth and eventually reducing the aflatoxin content will provide a valuable alternative to control strategies used in aflatoxin contamination management.

Keywords: aflatoxin, microorganism bacteria, biocontrol, beneficial microbes

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Authors: Luis E. Zapata, Sergio Ruiz, María F. Mantilla, Jhon A. Villamizar

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Sand as fine aggregate for concrete production needs a feasible substitute due to several environmental issues. In this work, a study of the behavior of self-compacting concrete mixtures under replacement of sand by iron slag from 0.0% to 50.0% of weight and variations of water/cementitious material ratio between 0.3 and 0.5 is presented. Control fresh state tests of Slump flow, T500, J-ring and L-box were determined. In the hardened state, compressive strength was determined and optimization from response surface analysis was performed. The study of the variables in the hardened state was developed based on inferential statistical analyses using central composite design methodology and posterior analyses of variance (ANOVA). An increase in the compressive strength up to 50% higher than control mixtures at 7, 14, and 28 days of maturity was the most relevant result regarding the presence of iron slag as replacement of natural sand. Considering the obtained result, it is possible to infer that iron slag is an acceptable alternative replacement material of the natural fine aggregate to be used in structural concrete.

Keywords: ANOVA, iron slag, response surface analysis, self-compacting concrete

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Authors: Zubier Arfan, Paul Johnson

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The electronification of financial markets and the rise of algorithmic trading has sparked a lot of interest from the mathematical community, for the market making-problem in particular. The research presented in this short paper solves the classic stochastic control problem in order to derive the strategy for a market-maker. It also shows how to calibrate and simulate the strategy with real limit order book data for back-testing. The ambiguity of limit-order priority in back-testing is dealt with by considering optimistic and pessimistic priority scenarios. The model, although it does outperform a naive strategy, assumes constant volatility, therefore, is not best suited to the LOB data. The Heston model is introduced to describe the price and variance process of the asset. The Trader's constant absolute risk aversion utility function is optimised by numerically solving a 3-dimensional Hamilton-Jacobi-Bellman partial differential equation to find the optimal limit order quotes. The results show that the stochastic volatility market-making model is more suitable for a risk-averse trader and is also less sensitive to calibration error than the constant volatility model.

Keywords: market-making, market-microsctrucure, stochastic volatility, quantitative trading

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Authors: Chaitanya H. Acharya, Pavan Kumar P., Gopalakrishna Narayana

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In the realm of aerodynamics, numerous vehicles incorporate moving components to enhance their performance. For instance, airliners deploy hydraulically operated flaps and ailerons during take-off and landing, while Formula 1 racing cars utilize hydraulic tubes and actuators for various components, including the Drag Reduction System (DRS). The DRS, consisting of a rear wing and adjustable flaps, plays a crucial role in overtaking manoeuvres. The DRS has two positions: the default position with the flaps down, providing high downforce, and the lifted position, which reduces drag, allowing for increased speed and aiding in overtaking. Swift deployment of the DRS during races is essential for overtaking competitors. The fluid flow over the rear wing flap becomes intricate during deployment, involving flow reversal and operational changes, leading to unsteady flow physics that significantly influence aerodynamic characteristics. Understanding the drag and downforce during DRS deployment is crucial for determining race outcomes. While experiments can yield accurate aerodynamic data, they can be expensive and challenging to conduct across varying speeds. Computational Fluid Dynamics (CFD) emerges as a cost-effective solution to predict drag and downforce across a range of speeds, especially with the rapid deployment of the DRS. This study employs the finite volume-based solver Ansys Fluent, incorporating dynamic mesh motions and a turbulent model to capture the complex flow phenomena associated with the moving rear wing flap. A dedicated section for the rare wing-flap is considered in the present simulations, and the aerodynamics of these sections closely resemble S1223 aerofoils. Before delving into the simulations of the rare wing-flap aerofoil, numerical results undergo validation using experimental data from an NLR flap aerofoil case, encompassing different flap angles at two distinct angles of attack was carried out. The increase in flap angle as increase in lift and drag is observed for a given angle of attack. The simulation methodology for the rare-wing-flap aerofoil case involves specific time durations before lifting the flap. During this period, drag and downforce values are determined as 330 N and 1800N, respectively. Following the flap lift, a noteworthy reduction in drag to 55 % and a decrease in downforce to 17 % are observed. This understanding is critical for making instantaneous decisions regarding the deployment of the Drag Reduction System (DRS) at specific speeds, thereby influencing the overall performance of the Formula 1 racing car. Hence, this work emphasizes the utilization of dynamic mesh motion methodology to predict the aerodynamic characteristics during the deployment of the DRS in a Formula 1 racing car.

Keywords: DRS, CFD, drag, downforce, dynamics mesh motion

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Authors: Andrea L. Arnett, Ann T. Packard, Yolanda I. Garces, Kenneth W. Merrell

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Objective: Pathologic response following neoadjuvant chemoradiation (CRT) has been associated with improved overall survival (OS). Conflicting results have been reported regarding the pathologic predictive value of positron emission tomography (PET) response in patients with stage III lung cancer. The aim of this study was to evaluate the correlation between post-treatment PET response and pathologic response utilizing novel FDG-PET parameters. Methods: This retrospective study included patients with non-metastatic, stage IIIA (N2) NSCLC cancer treated with CRT followed by resection. All patients underwent PET prior to and after neoadjuvant CRT. Univariate analysis was utilized to assess correlations between PET response, nodal clearance, pCR, and near-complete pathologic response (defined as the microscopic residual disease or less). Maximal standard uptake value (SUV), standard uptake ratio (SUR) [normalized independently to the liver (SUR-L) and blood pool (SUR-BP)], metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were measured pre- and post-chemoradiation. Results: A total of 44 patients were included for review. Median age was 61.9 years, and median follow-up was 2.6 years. Histologic subtypes included adenocarcinoma (72.2%) and squamous cell carcinoma (22.7%), and the majority of patients had the T2 disease (59.1%). The rate of pCR and near-complete pathologic response within the primary lesion was 28.9% and 44.4%, respectively. The average reduction in SUVmₐₓ was 9.2 units (range -1.9-32.8), and the majority of patients demonstrated some degree of favorable treatment response. SUR-BP and SUR-L showed a mean reduction of 4.7 units (range -0.1-17.3) and 3.5 units (range –1.7-12.6), respectively. Variation in PET response was not significantly associated with histologic subtype, concurrent chemotherapy type, stage, or radiation dose. No significant correlation was found between pathologic response and absolute change in MTV or TLG. Reduction in SUVmₐₓ and SUR were associated with increased rate of pathologic response (p ≤ 0.02). This correlation was not impacted by normalization of SUR to liver versus mediastinal blood pool. A threshold of > 75% decrease in SUR-L correlated with near-complete response, with a sensitivity of 57.9% and specificity of 85.7%, as well as positive and negative predictive values of 78.6% and 69.2%, respectively (diagnostic odds ratio [DOR]: 5.6, p=0.02). A threshold of >50% decrease in SUR was also significantly associated pathologic response (DOR 12.9, p=0.2), but specificity was substantially lower when utilizing this threshold value. No significant association was found between nodal PET parameters and pathologic nodal clearance. Conclusions: Our results suggest that treatment response to neoadjuvant therapy as assessed on PET imaging can be a predictor of pathologic response when evaluated via SUV and SUR. SUR parameters were associated with higher diagnostic odds ratios, suggesting improved predictive utility compared to SUVmₐₓ. MTV and TLG did not prove to be significant predictors of pathologic response but may warrant further investigation in a larger cohort of patients.

Keywords: lung cancer, positron emission tomography (PET), standard uptake ratio (SUR), standard uptake value (SUV)

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Authors: Dina Muharib

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Specific metabolic challenges are present following spinal cord injury. The acute stage is characterized by a reduction in metabolic activity, as well as a negative nitrogen balance that cannot be corrected, even with aggressive nutritional support. Metabolic demands need to be accurately monitored to avoid overfeeding. Enteral feeding is the optimal route following SCI. When oral feeding is not possible, nasogastric, followed by nasojejunal, then by percutaneous endoscopic gastrostomy, if necessary, is suggested.

Keywords: SCI, energy, protein, nutrition assessment, eneral feeding, nitrogen balance

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Authors: M. F. Páramo, F. Cadaveira, M. S. Rodríguez

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The first year at university is a critical period for personal-emotional and academic adjustment in emerging adults. Moreover, some studies show that alcohol consumption increases in young adults on transition to university. The main purpose of this study was to analyze the impact of hazardous alcohol consumption and gender on adjustment to university, understood as a multidimensional construct involving an array of demands. A sample of 300 first year students in Spain completed the Student Adaptation to College Questionnaire (SACQ) and the Alcohol Use Disorders Identification Test (AUDIT). Examination of the data by analysis of variance revealed that adjustment to university was lower in the students undertaking hazardous alcohol consumption than in the other students. Surprisingly, the personal-emotional adjustment of students with hazardous alcohol consumption was not lower than in the other students. Analysis of the gender effect revealed that levels of personal-emotional adjustment were higher in males than in females. This is our first study examining the influence of alcohol consumption on university adjustment. Future research should examine this relationship more closely, with the aim of designing public health strategies focused on limiting abusive consumption of alcohol in university students.

Keywords: alcohol consumption, first year university students, gender, SACQ

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Authors: Ana Maria Girotti Sperandio, Jussara Conceição Guarnieri, Lauro Luiz Francisco Filho, Ana Claudia Martins Alves, Adriana Aparecida Carneiro Rosa

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The urban planning of a city should contemplate the construction of healthy spaces to provide quality of life for people. In a Brazilian municipality located 180 km from the capital of São Paulo with around 27,000 thousand inhabitants, the federal government made possible a program that allows the improvement of the quality of life of the inhabitants through the practice of physical activity. To describe health promotion strategies in the city that collaborate in the reduction of chronic non-communicable diseases (CDNT) and the improvement the quality of its residents. Considering the CDNT as a fundamental public health concern in different countries, the methodology of this work considered the different actions of health promotion that occurred in the city for the implementation of the Polo Health Academy with the objective of increasing the population's access to places that could develop targeted physical activities. As an instrument, it used records of participants of this academy such as: assessment sheets, evolution, photos, filming and daily reports of physical activities. Results: The implantation and implementation process of the Polo Health Academy in the city of Conchal / SP / Brazil was in accordance with the principles and values of the National Health Promotion Policy (PNaPS) in Brazil and with the city statute, that provides improvement in the quality of life of the Brazilian population. An increase was observed in the number of participants in different hours practicing physical activities in the territory linked to one of the five Health Units, showing the program provides that happiness and well-being to the students. The Brazilian health promotion policy, combined with the city’s development policy, provides the population with access to programs that stimulate the reduction of CDNTs, confirming the urban planning of a healthy city.

Keywords: health city, health promotion, physical activity, urban planning

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Authors: Siewchuiang Sia, Gimcheong Tan

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Bacteriophages are the most abundant and genetically diverse living entities on earth; they help in regulating and maintaining microbial diversity and balance in its natural ecosystem. In this study, the infectivity of SFN6B tailed phage was investigated in various water samples. Host bacteria (Shigella flexneri) were spiked in sterilized environmental and domestic water samples, followed by SFN6B treatment. Two incubation conditions were selected for this study, 37 oC and room temperature. S. flexneri and SFN6B viability were monitored hourly for consecutive 7 hours and extended viability study for consecutive 4 days. Absorbance of all bacteria spiked water samples were taken to monitor the bacteria count. Results showed reduction in the absorbance of the SFN6B treated water sample as compared to negative control, indicating reduction in bacterial count either due to negative growth or lysis by the lytic bacteriophage. Consistent with the result, SFN6B titer increases for first two days. However, prolong incubation of these cultures reaches equilibrium, between phage and bacteria. Temperature and water sample source also influence the interaction between S. flexneri and SFN6B. Stronger interaction was observed in 37oC as compared to room temperature, where higher bacteria count and phage titer increase were recorded. Availability of nutrient in water sample also plays a crucial role in the interaction between bacteria and phage. Higher nutrient level, such as lake and river waters were observed to give better infectivity and viability of both bacteria and phage as compared to tab water. It is believed that S. flexneri continue to remain viable and able to grow in the present of SFN6B bacteriophage, but the number was closely regulated by surrounding phages. This allows better understanding of the characteristics of SFN6B that could serve as the basis for future studies and applications.

Keywords: bacteriophage, Shigella flexneri, infection, microbial diversity

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Authors: Anna Drabczyk, Sonia Kudlacik-Kramarczyk, Dagmara Malina, Bozena Tyliszczak, Agnieszka Sobczak-Kupiec

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Nowadays, nano-size materials are very popular group of materials among scientists. What is more, these materials find an application in a wide range of various areas. Therefore constantly increasing demand for nanomaterials including metallic nanoparticles such as silver of gold ones is observed. Therefore, new routes of their preparation are sought. Considering potential application of nanoparticles, it is important to select an adequate methodology of their preparation because it determines their size and shape. Among the most commonly applied methods of preparation of nanoparticles chemical and electrochemical techniques are leading. However, currently growing attention is directed into the biological or biochemical aspects of syntheses of metallic nanoparticles. This is associated with a trend of developing of new routes of preparation of given compounds according to the principles of green chemistry. These principles involve e.g. the reduction of the use of toxic compounds in the synthesis as well as the reduction of the energy demand or minimization of the generated waste. As a result, a growing popularity of the use of such components as natural plant extracts, infusions or essential oils is observed. Such natural substances may be used both as a reducing agent of metal ions and as a stabilizing agent of formed nanoparticles therefore they can replace synthetic compounds previously used for the reduction of metal ions or for the stabilization of obtained nanoparticles suspension. Methods that proceed in the presence of previously mentioned natural compounds are environmentally friendly and proceed without the application of any toxic reagents. Methodology: Presented research involves preparation of silver nanoparticles using selected plant extracts, e.g. artichoke extract. Extracts of natural origin were used as reducing and stabilizing agents at the same time. Furthermore, syntheses were carried out in the presence of additional polymeric stabilizing agent. Next, such features of obtained suspensions of nanoparticles as total antioxidant activity as well as content of phenolic compounds have been characterized. First of the mentioned studies involved the reaction with DPPH (2,2-Diphenyl-1-picrylhydrazyl) radical. The content of phenolic compounds was determined using Folin-Ciocalteu technique. Furthermore, an essential issue was also the determining of the stability of formed suspensions of nanoparticles. Conclusions: In the research it was demonstrated that metallic nanoparticles may be obtained using plant extracts or infusions as stabilizing or reducing agent. The methodology applied, i.e. a type of plant extract used during the synthesis, had an impact on the content of phenolic compounds as well as on the size and polydispersity of obtained nanoparticles. What is more, it is possible to prepare nano-size particles that will be characterized by properties desirable from the viewpoint of their potential application and such an effect may be achieved with the use of non-toxic reagents of natural origin. Furthermore, proposed methodology stays in line with the principles of green chemistry.

Keywords: green chemistry principles, metallic nanoparticles, plant extracts, stabilization of nanoparticles

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Authors: Rakesh Namdeti

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Toxic dyes found in industrial effluent must be treated before being disposed of due to their harmful impact on human health and aquatic life. Thus, Musa acuminata (Banana Leaves) was employed in the role of a biosorbent in this work to get rid of methylene blue derived from a synthetic solution. The effects of five process parameters, such as temperature, pH, biosorbent dosage, and initial methylene blue concentration, using a central composite design (CCD), and the percentage of dye clearance were investigated. The response was modelled using a quadratic model based on the CCD. The analysis of variance revealed the most influential element on experimental design response (ANOVA). The temperature of 44.30C, pH of 7.1, biosorbent dose of 0.3 g, starting methylene blue concentration of 48.4 mg/L, and 84.26 percent dye removal were the best conditions for Musa acuminata (Banana leave powder). At these ideal conditions, the experimental percentage of biosorption was 76.93. The link between the estimated results of the developed ANN model and the experimental results defined the success of ANN modeling. As a result, the study's experimental results were found to be quite close to the model's predicted outcomes.

Keywords: Musa acuminata, central composite design, methylene blue, artificial neural network

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Authors: Hala M. Abdelkarem, Abeer H. Gafeer

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The metabolic syndrome (Mts) is a constellation of risk factors. The main objective of this study is to compare the ameliorating effect of metformin, lipitor, orilstate, lipoic acid and carnitin on insulin, lipid profile, leptin, adenonectin levels in metabolic syndrom (high fructose fed rats HF). Seventy male albino rats were divided into seven groups. G1: normal control. G2: G7 rats fed HF for 8wks. After four wk HF feeding, G3, G4, G5, G6, and G7 were orally administered (200 mg/kg daily) metformin, lipitor, orilstate, lipoic acid and carnitin respectively. All drugs were adminiseterd once daily. After 8 weeks of feeding, a significant increase in blood glucose level was observed in HF fed rats compared to normal rats, but this increase was significantly decreased after administration of metformin and lipitor. The raised of serum insulin level in HF fed rats was significantly decreased after administration of lipoic, carnitin, metformin. Significant higher concentrations of triglycerides (TG), total cholesterol & low density lipoprotein cholesterol (LDL- C) were observed in HF fed rats and these increases were significantly lowered after the administration of all the previous drugs. There was a significant decrease in serum high density lipoprotein cholesterol (HDL-C) in HF group administration of all drugs alleviates this reduction. The increased of serum leptin level in HF group was decreased significantly in met and orilstate groups. Whereas the reduction of serum adiponectin level in HF fed rats was increased in Lipitor, carnitin, orilstate groups. These data suggested that benefial effect of metformin, lipitor, orilstate, lipoic acid carnitin in reducing risk for people with decreased insulin sensitivity, increased oxidative stress and hyperlipidemia such as those with the metabolic syndrome or type 2 diabetes.

Keywords: metabolic syndrome, diabetes, proinflammation, antioxidants

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Authors: Shehu, B., Muhammad, B. F., Madigawa, I. L., H. A. Alkali

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The study was conducted to assess heifer camel behavior and live weight changes on native range supplemented with different energy levels. A total of nine camels aged between 2 and 3 years were randomly allotted into three groups and supplemented with 3400, 3600 and 3800 Kcal and designated A, B and C, respectively. The data obtained was analyzed for variance in a Completely Randomized Design. The heifers utilized average of 371.70 min/day (64% of daylight time) browsing on native pasture and 2.30 min/day (6%) sand bathing. A significantly higher mean time was spent by heifers on browsing Leptadenia hastata (P<0.001), Dichrostachys cinerea (P<0.01), Acacia nilotica (P<0.001) and Ziziphus spina-christi (P<0.05) in early dry season (January). No significant difference was recorded on browsing time on Tamarindus indica, Adansonia digitata, Piliostigma reticulatum, Parkia biglobosaand Azadirachta indica. No significant (P<0.05) liveweight change was recorded on she-camels due to the three energy levels. It was concluded that nutritive browse species in the study area could meet camel nutrient requirements including energy. Further research on effect of period on camel nutrients requirement in different physiological conditions is recommended.

Keywords: heifer, camel, grazing, pasture

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Authors: Farshad Ghazalian, Laleh Hakemi, Lotfali Pourkazemi, Maryam Ameri, Seyed Hossein Alavi

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Background: The use of whole body vibration (WBV) as an exercise method has rapidly increased over the last decade. The aim of this study was to evaluate long term effects of different amplitudes of whole body vibration training with progressive frequencies on lipid profile of young healthy men. Materials and methods: Thirty three healthy male students were divided randomly in three groups: high amplitude vibration group (n=11), low amplitude vibration group (n=11), and control group (n=11). The vibration training consisted of 5 week whole-body vibration 3 times a week with amplitudes 4 and 2 mm and progressive frequencies from 25 Hz with increments of 5 Hz weekly. Concentrations TG, HDL, LDL, cholesterol, and VLDL before and after 5 weeks of training were measured in plasma samples. Statistical analysis was done using one way analysis of variance. P<0.05 was considered statistically significant. Results: The most important result of the present study is finding no favorable changes of 5-week vibration training with different amplitudes on blood lipid profiles. Discussion and conclusions: It was emphasized that in vibration training there should be a relationship between intensity and volume of exercise and lipid responses in order to improve blood lipoprotein profiles.

Keywords: long term, body, vibration training, lipid

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Authors: Adji Achmad Rinaldo Fernandes

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SEM analysis is a complex multivariate analysis because it involves a number of exogenous and endogenous variables that are interconnected to form a model. The measurement model is divided into two, namely, the reflective model (reflecting) and the formative model (forming). Before carrying out further tests on SEM, there are assumptions that must be met, namely the linearity assumption, to determine the form of the relationship. There are three modeling approaches to path analysis, including parametric, nonparametric and semiparametric approaches. The aim of this research is to develop semiparametric SEM and obtain the best model. The data used in the research is secondary data as the basis for the process of obtaining simulation data. Simulation data was generated with various sample sizes of 100, 300, and 500. In the semiparametric SEM analysis, the form of the relationship studied was determined, namely linear and quadratic and determined one and two knot points with various levels of error variance (EV=0.5; 1; 5). There are three levels of closeness of relationship for the analysis process in the measurement model consisting of low (0.1-0.3), medium (0.4-0.6) and high (0.7-0.9) levels of closeness. The best model lies in the form of the relationship X1Y1 linear, and. In the measurement model, a characteristic of the reflective model is obtained, namely that the higher the closeness of the relationship, the better the model obtained. The originality of this research is the development of semiparametric SEM, which has not been widely studied by researchers.

Keywords: semiparametric SEM, measurement model, structural model, reflective model, formative model

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Authors: Shahrzad Zolfagharnassab, Abdul Rashid Mohamed Shariff, Siti Khairunniza Bejo

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Conventional methods for nutrient soil mapping are based on laboratory tests of samples that are obtained from surveys. The time and cost involved in gathering and analyzing soil samples are the reasons that researchers use Predictive Soil Mapping (PSM). PSM can be defined as the development of a numerical or statistical model of the relationship among environmental variables and soil properties, which is then applied to a geographic database to create a predictive map. Kriging is a group of geostatistical techniques to spatially interpolate point values at an unobserved location from observations of values at nearby locations. The main problem with using kriging as an interpolator is that it is excessively data-dependent and requires a large number of closely spaced data points. Hence, there is a need to minimize the number of data points without sacrificing the accuracy of the results. In this paper, an Artificial Neural Networks (ANN) scheme was used to predict macronutrient values at un-sampled points. ANN has become a popular tool for prediction as it eliminates certain difficulties in soil property prediction, such as non-linear relationships and non-normality. Back-propagation multilayer feed-forward network structures were used to predict nitrogen, phosphorous and potassium values in the soil of the study area. A limited number of samples were used in the training, validation and testing phases of ANN (pattern reconstruction structures) to classify soil properties and the trained network was used for prediction. The soil analysis results of samples collected from the soil survey of block C of Sawah Sempadan, Tanjung Karang rice irrigation project at Selangor of Malaysia were used. Soil maps were produced by the Kriging method using 236 samples (or values) that were a combination of actual values (obtained from real samples) and virtual values (neural network predicted values). For each macronutrient element, three types of maps were generated with 118 actual and 118 virtual values, 59 actual and 177 virtual values, and 30 actual and 206 virtual values, respectively. To evaluate the performance of the proposed method, for each macronutrient element, a base map using 236 actual samples and test maps using 118, 59 and 30 actual samples respectively produced by the Kriging method. A set of parameters was defined to measure the similarity of the maps that were generated with the proposed method, termed the sample reduction method. The results show that the maps that were generated through the sample reduction method were more accurate than the corresponding base maps produced through a smaller number of real samples. For example, nitrogen maps that were produced from 118, 59 and 30 real samples have 78%, 62%, 41% similarity, respectively with the base map (236 samples) and the sample reduction method increased similarity to 87%, 77%, 71%, respectively. Hence, this method can reduce the number of real samples and substitute ANN predictive samples to achieve the specified level of accuracy.

Keywords: artificial neural network, kriging, macro nutrient, pattern recognition, precision farming, soil mapping

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Authors: Dan Wang

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Sandplay therapy is a Jungian psychological therapy developed by Dora Kalff in 1956. In sandplay therapy, the client first makes a sandtray with various miniatures and then has a communication with the therapist based on the sandtray. The special method makes sandplay therapy has great assessment potential. With regarding that the core treatment hypothesis of sandplay therapy - the self-healing power, is very similar to resilience. This study tries to use sandplay to evaluate psychological resilience. Participants are 107 undergraduates recruited from three public universities in China who were required to make an initial sandtray and to complete the Ego-Resiliency Scale (ER89) respectively. First, a 28- category General Sandtray Coding Manual (GSCM) was developed based on literature on sandplay therapy. Next, using GSCM to code the 107 initial sandtrays and conducted correlation analysis and regression analysis between all GSCM categories and ER89. Results show three categories (i.e., vitality, water types, and relationships) of sandplay account for 36.6% of the variance of ego-resilience and form the four-point Likert-type Sandtray Projective Test of Resilience (SPTR). Finally, it is found that SPTR dimensions and total score all have good inter-rater reliability, ranging from 0.89 to 0.93. This study provides an alternative approach to measure psychological resilience and can help to guide clinical social work.

Keywords: sandplay therapy, psychological resilience, measurement, college students

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Authors: H. C. Chinwenyi, H. D. Ibrahim, F. A. Ahmed

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In modern financial mathematics, valuing derivatives such as options is often a tedious task. This is simply because their fair and correct prices in the future are often probabilistic. This paper examines three different Stochastic Differential Equation (SDE) models in finance; the Constant Elasticity of Variance (CEV) model, the Balck-Karasinski model, and the Heston model. The various Martingales option price valuation formulas for these three models were obtained using the replicating portfolio method. Also, the numerical solution of the derived Martingales options price valuation equations for the SDEs models was carried out using the Monte Carlo method which was implemented using MATLAB. Furthermore, results from the numerical examples using published data from the Nigeria Stock Exchange (NSE), all share index data show the effect of increase in the underlying asset value (stock price) on the value of the European Put Option for these models. From the results obtained, we see that an increase in the stock price yields a decrease in the value of the European put option price. Hence, this guides the option holder in making a quality decision by not exercising his right on the option.

Keywords: equivalent martingale measure, European put option, girsanov theorem, martingales, monte carlo method, option price valuation formula

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Authors: Marco Barassi, Nicola Spagnolo

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This paper uses a DCC-GARCH model framework to examine mean and volatility spillovers (i.e. causality in mean and variance) dynamics between financial centers and the stock market indexes of the BRICS countries. In addition, tests for changes in the transmission mechanism are carried out by first testing for structural breaks and then setting a dummy variable to control for the 2008 financial crises. We use weekly data for nine countries, four financial centers (Germany, Japan, UK and USA) and the five BRICS countries (Brazil, Russia, India, China and South Africa). Furthermore, we control for monetary policy using domestic interest rates (90-day Treasury Bill interest rate) over the period 03/1/1990 - 04/2/2014, for a total of 1204 observations. Results show that the 2008 financial crises changed the causality dynamics for most of the countries considered. The same pattern can also be observed in conditional correlation showing a shift upward following the turbulence associated to the 2008 crises. The magnitude of these effects suggests a leading role played by the financial centers in effecting Brazil and South Africa, whereas Russia, India and China show a higher degree of resilience.

Keywords: financial crises, DCC-GARCH model, volatility spillovers, economics

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Authors: E. Osazee, L. U. Bashir

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This study was conducted at the Department of Biological Sciences, Usmanu Danfodiyo University, Sokoto, Nigeria, to determine the effects of different weights of cow dung on indigenous bacterial isolates in remediation of crude oil contaminated soils. The soil (1kg) was contaminated with 20g of crude oil and this was treated with three (40g, 80g and 120g) weights of cow dung. The soils were amended after two weeks of crude oil contamination. Soil samples were collected from the plastic bags for microbiological analyses. The isolates were cultured to test their ability to grow on crude oil. The ability of the isolates to utilize the crude oil was determined using media dilution technique. Bacteria such as Proteus mirabilis, Bacillus lacterosporus, Morganella morganii, Serratia marcescens and Bacillus alvei were isolated. The variables measured were heterotrophic bacterial populations, hydrocarbon utilizing bacterial populations and the percentage of crude oil degraded in the soils. Data collected were subjected to analysis of variance (ANOVA). Results obtained indicated that all the different weights of cow dung showed appreciable effect in crude oil decontamination. Based on the findings of the experiments, it could be deduced that 120g of cow dung promoted higher degradation of hydrocarbons. Thus, it should be recommended for remediation of crude oil contaminated soil in the study area.

Keywords: crude oil, cow dung, amendment, bioremediation, decontamination

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Authors: Abdulrahman Yarali

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The advancement of technology never stops because the demands for improved internet and communication connectivity are increasing. Just as 5G networks are rolling out, the world has begun to talk about the sixth-generation networks (6G). The semantics of 6G are more or less the same as 5G networks because they strive to boost speeds, machine-to-machine (M2M) communication, and latency reduction. However, some of the distinctive focuses of 6G include the optimization of networks of machines through super speeds and innovative features. This paper discusses many aspects of the technologies, architectures, challenges, and opportunities of 6G wireless communication systems.

Keywords: 6G, characteristics, infrastructures, technologies, AI, ML, IoT, applications

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Authors: F. S. Al-Anzi, M. Sarfraz, A. Elmi, A. R. Khan

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Researchers are responding to the environmental challenges of Kuwait in localized, innovative, effective and economic ways. One of the vital and significant examples of the natural challenges is lack or water and desertification. In this research, the project team focuses on redesigning a prototype, using Value Engineering Methodology, which would provide similar functionalities to the well-known technology of Waterboxx kits while reducing the capital and operational costs and simplifying the process of manufacturing and usability by regular farmers. The design employs used tires and recycled plastic sheets as raw materials. Hence, this approach is going to help not just fighting desertification but also helping in getting rid of ever growing huge tire dumpsters in Kuwait, as well as helping in avoiding hazards of tire fires yielding in a safer and friendlier environment. Several alternatives for implementing the prototype have been considered. The best alternative in terms of value has been selected after thorough Function Analysis System Technique (FAST) exercise has been developed. A prototype has been fabricated and tested in a controlled simulated lab environment that is being followed by real environment field testing. Water and soil analysis conducted on the site of the experiment to cross compare between the composition of the soil before and after the experiment to insure that the prototype being tested is actually going to be environment safe. Experimentation shows that the design was equally as effective as, and may exceed, the original design with significant savings in cost. An estimated total cost reduction using the VE approach of 43.84% over the original design. This cost reduction does not consider the intangible costs of environmental issue of waste recycling which many further intensify the total savings of using the alternative VE design. This case study shows that Value Engineering Methodology can be an important tool in innovating new designs for reducing costs.

Keywords: desertification, functional analysis, scrap tires, value engineering, waste recycling, water irrigation rationing

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Authors: Adam J. Carinci

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Background: The opioid epidemic is the most pressing healthcare crisis of our time. There is increasing recognition that opioids have limited long-term efficacy and are associated with hyperalgesia, addiction, and increased morbidity and mortality. Therefore, alternative strategies to combat chronic pain are paramount. We initiated a multicenter retrospective case series to review the efficacy of DRG stimulation in facilitating opioid tapering, opioid discontinuation and as a viable alternative to chronic opioid therapy. Purpose: The dorsal root ganglion (DRG) plays a key role in the development and maintenance of pain. Recent innovations in neuromodulation, specifically, dorsal root ganglion stimulation, offers an effective alternative to opioids in the treatment of chronic pain. This retrospective case series demonstrates preliminary evidence that DRG stimulation facilitates opioid tapering, opioid discontinuation and presents a viable alternative to chronic opioid therapy. Procedure: This small multicenter retrospective case series provides preliminary evidence that DRG stimulation facilitates opioid weaning, opioid tapering and is a viable option to opioid therapy in the treatment of chronic pain. A retrospective analysis was completed. Visual analog scale pain scores and pain medication usage were collected at the baseline visit and after four weeks, 3 months and 6 months of treatment. Ten consecutive patients across two study centers were included. The pain was rated 7.38 at baseline and decreased to 1.50 at the 4-week follow-up, a reduction of 79.5%. All patients significantly decreased their opioid pain medication use with an average > 30% reduction in morphine equivalents and four were able to discontinue their medications entirely. Conclusion: This Retrospective case series demonstrates preliminary evidence that DRG stimulation facilitates opioid tapering, opioid discontinuation and presents a viable alternative to chronic opioid therapy.

Keywords: dorsal root ganglion, neuromodulation, opioid sparing, stimulation

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Authors: Kun Li, Yuzheng Liu, Xiuqi Fan

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High-security standard and high efficiency of screening seem to be contradictory to each other in the airport security check process. Improving the efficiency as far as possible while maintaining the same security standard is significantly meaningful. This paper utilizes the knowledge of Operation Research and Stochastic Process to establish mathematical models to explore this problem. We analyze the current process of airport security check and use the M/G/1 and M/G/k models in queuing theory to describe the process. Then we find the least efficient part is the pre-check lane, the bottleneck of the queuing system. To improve passenger throughput and reduce the variance of passengers’ waiting time, we adjust our models and use Monte Carlo method, then put forward three modifications: adjust the ratio of Pre-Check lane to regular lane flexibly, determine the optimal number of security check screening lines based on cost analysis and adjust the distribution of arrival and service time based on Monte Carlo simulation results. We also analyze the impact of cultural differences as the sensitivity analysis. Finally, we give the recommendations for the current process of airport security check process.

Keywords: queue theory, security check, stochatic process, Monte Carlo simulation

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Authors: Omotoyosi Bilikies Ilori, Adekunle Saheed Ajisebiyawo

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After the Second World War, there was an emergence of a new stage of capitalist globalization with its Neo-liberal ideology. There were global economic and political restructurings that affected third-world countries like Nigeria. Neo-liberalism is the driving force of globalization, which is the latest manifestation of imperialism that engenders endemic poverty in Nigeria. Poverty is severe and widespread in Nigeria. Poverty entails a situation where a person lives on less than one dollar per day and has no access to basic necessities of life. Poverty is inhuman and a breach of human rights. The Nigerian government initiated some strategies in the past to help in poverty reduction. Neo-liberalism manifested in the Third World, such as Nigeria, through the privatization of public enterprises, trade liberalization, and the rollback of the state investments in providing important social services. These main ideas of Neo-liberalism produced poverty in Nigeria and also encouraged the abandonment of the social contract between the government and the people. There is thus a gap in the provision of social services and subsidies for the masses, all of which Neo-liberal ideological positions contradict. This paper is a qualitative study which draws data from secondary sources. The theoretical framework is anchored on the market theory of capitalist globalization and public choice theory. The objectives of this study are to (i) examine the impacts of Neo-liberalism on poverty in Nigeria as a typical example of a Third World country and (ii) find out the effects of Neo-liberalism on the provision of social services and subsidies and employment. The findings from this study revealed that (i) the adoption of the Neo-liberal ideology by the Nigerian government has led to increased poverty and poor provision of social services and employment in Nigeria; and (ii) there is an increase in foreign debts which compounds poverty situation in Nigeria. This study makes the following recommendations: (i) Government should adopt strategies that are pro-poor to eradicate poverty; (ii) The Trade Unions and the masses should develop strategies to challenge Neo-liberalism and reject Neo-liberal ideology.

Keywords: neo-liberalism, poverty, employment, poverty reduction, structural adjustment programme

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Authors: H. Aripin, I. Made Joni, Edvin Priatna, Nundang Busaeri, Svilen Sabchevski

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In this investigation, manganese has been produced from medium grade manganese ore from Karangnunggal mine (West Java, Indonesia). The ores were grinded using a jar mill to pass through a 150 mesh sieve. The effects of keeping it at a temperature of 1200 °C in methane gas on the structural properties have been studied. The material’s properties have been characterized on the basis of the experimental data obtained using X-ray fluorescence (XRF), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. It has been found that the ore contains MnO₂ as the main constituents at about 46.80 wt.%. It can be also observed that the ore particles are agglomerated forming dense grains with different texture and morphology. The irregular-shaped grains with dark contrast, the large brighter grains, and smaller grains with bright texture and smooth surfaces are associated with the presence of manganese, calcium, and quartz, respectively. From XRD patterns, MnO₂ is reduced to hausmannite (Mn₃O₄), manganosite (MnO) and manganese carbide (Mn₇C₃). At a temperature of 1200°C the keeping time does not have any effect on the formation of crystals and the crystalline phases remain almost unchanged in the time range from 15 to 90 minutes. An increase of the keeping time up to 45 minutes during the sintering process leads to an increase of the MnO concentration, while at 90 minutes, the concentration decreases. At longer keeping times the excess reaction of the methane gas and manganese oxide in the ore causes an increase of carbon deposition. As a result, it blocks the particle surface and then hinders the reduction process of manganese oxide. From FTIR spectrum allows one to explain that the appearance of C=O stretching mode arises from absorption of atmospheric methane and manganese oxide of the ore. The intensity of this band increases with increasing the keeping time, indicating an increase of carbon deposition on the surface of manganese oxide.

Keywords: manganese, medium grade manganese ore, structural properties, keeping the temperature, carbon deposition

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Authors: Mário Ernesto Sitoe, Orlando Zacarias

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University education is influenced by several factors that range from the adoption of strategies to strengthen the whole process to the academic performance improvement of the students themselves. This work uses data mining techniques to develop a predictive model to identify students with a tendency to evasion and retention. To this end, a database of real students’ data from the Department of University Admission (DAU) and the Department of Mathematics and Informatics (DMI) was used. The data comprised 388 undergraduate students admitted in the years 2009 to 2014. The Weka tool was used for model building, using three different techniques, namely: K-nearest neighbor, random forest, and logistic regression. To allow for training on multiple train-test splits, a cross-validation approach was employed with a varying number of folds. To reduce bias variance and improve the performance of the models, ensemble methods of Bagging and Stacking were used. After comparing the results obtained by the three classifiers, Logistic Regression using Bagging with seven folds obtained the best performance, showing results above 90% in all evaluated metrics: accuracy, rate of true positives, and precision. Retention is the most common tendency.

Keywords: evasion and retention, cross-validation, bagging, stacking

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Authors: Tzong-Shing Cheng, Chen Pei Chen, Shu-Wei Chen

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The purpose of this research is to apply Unified Theory of Acceptance and Use of Technology (UTAUT) model to investigate the factors that influence elementary school teacher’s behavior of using e-books. Based on the literature review, a questionnaire was modified and used to test the elementary school teachers in Changhua. A total of 420 questionnaires were administered and 364 of them were returned, including 328 valid and 36 invalid questionnaires. The effective response rate is 78%. The methods of data analysis include descriptive statistics, factor analysis, Pearson’s correlation coefficient, one way analysis of variance (ANOVA) and simple regression analysis. The results show that: 1. There were significant difference in the Elementary school teachers’ “Performance Expectancy”, “Effort Expectancy”, “Social Influence”, and “Facilitating Conditions” depending on their different “Demographic Variables”. 2. “Performance Expectancy” and “Behavioral Intention to Use” are positively correlated. 3. “Effort Expectancy” and “Behavioral Intention to Use” are positively correlated. 4. There was no significant relationship between “Social Influence” and “Behavioral Intention to Use”. 5. There was significant relationship between “Facilitating Conditions” and “Use Behavior”.

Keywords: e-books, UTAUT, elementary school teacher, behavioral intention to use

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