Search results for: composite index
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 5397

Search results for: composite index

1137 Green Public Procurement in Open Access and Traditional Journals: A Comparative Bibliometric Analysis

Authors: Alonso-Cañadas J., Galán-Valdivieso F., Saraite-Sariene L., García-Tabuyo M., Alonso-Morales N.

Abstract:

Green Public Procurement (GPP) has recently gained attention in the academic and policy arenas since climate change has shown the need to be addressed by both private companies and public entities. Such growing interest motivates this article, aiming to explore the most influential journals, publishers, categories, and topics, as well as the recent trends and future research lines in GPP. Based on the Web of Science database, 578 articles from 2004 to February 2022 devoted to GPP are analyzed using Bibliometrix, an R-tool to perform bibliometric analysis, and Google’s Big Query and Data Studio. This article introduces a variety of findings. First, the most influential journals by far are “Journal of Cleaner Production” and “Sustainability,” differing in that the latter is open access while the former publishes via traditional subscription. This result also occurs regarding the main publishers (Elsevier and MDPI). These features lead us to split the sample into open-access journals and traditional journals to deepen into the similarities and differences between them, confirming that traditional journals exhibit a higher degree of influence in the literature than their open-access counterparts in terms of the number of documents, number of citations and impact (according to the H index). Second, this research also highlights the recent emergence of green-related terms (sustainable, environment) and, parallelly, the increase in categorizing GPP papers in “green” WoS categories, particularly since 2019. Finally, a number of related topics are emerging and will lead the research, such as food security, infrastructures, and implementation barriers of GPP.

Keywords: bibliometric analysis, green public procurement, open access, traditional journals

Procedia PDF Downloads 88
1136 Building Biodiversity Conservation Plans Robust to Human Land Use Uncertainty

Authors: Yingxiao Ye, Christopher Doehring, Angelos Georghiou, Hugh Robinson, Phebe Vayanos

Abstract:

Human development is a threat to biodiversity, and conservation organizations (COs) are purchasing land to protect areas for biodiversity preservation. However, COs have limited budgets and thus face hard prioritization decisions that are confounded by uncertainty in future human land use. This research proposes a data-driven sequential planning model to help COs choose land parcels that minimize the uncertain human impact on biodiversity. The proposed model is robust to uncertain development, and the sequential decision-making process is adaptive, allowing land purchase decisions to adapt to human land use as it unfolds. The cellular automata model is leveraged to simulate land use development based on climate data, land characteristics, and development threat index from NASA Socioeconomic Data and Applications Center. This simulation is used to model uncertainty in the problem. This research leverages state-of-the-art techniques in the robust optimization literature to propose a computationally tractable reformulation of the model, which can be solved routinely by off-the-shelf solvers like Gurobi or CPLEX. Numerical results based on real data from the Jaguar in Central and South America show that the proposed method reduces conservation loss by 19.46% on average compared to standard approaches such as MARXAN used in practice for biodiversity conservation. Our method may better help guide the decision process in land acquisition and thereby allow conservation organizations to maximize the impact of limited resources.

Keywords: data-driven robust optimization, biodiversity conservation, uncertainty simulation, adaptive sequential planning

Procedia PDF Downloads 192
1135 Accessibility Assessment of School Facilities Using Geospatial Technologies: A Case Study of District Sheikhupura

Authors: Hira Jabbar

Abstract:

Education is vital for inclusive growth of an economy and a critical contributor for investment in human capital. Like other developing countries, Pakistan is facing enormous challenges regarding the provision of public facilities, improper infrastructure planning, accelerating rate of population and poor accessibility. The influence of the rapid advancement and innovations in GIS and RS techniques have proved to be a useful tool for better planning and decision making to encounter these challenges. Therefore present study incorporates GIS and RS techniques to investigate the spatial distribution of school facilities, identifies settlements with served and unserved population, finds potential areas for new schools based on population and develops an accessibility index to evaluate the higher accessibility for schools. For this purpose high-resolution worldview imagery was used to develop road network, settlements and school facilities and to generate school accessibility for each level. Landsat 8 imagery was utilized to extract built-up area by applying pre and post-processing models and Landscan 2015 was used to analyze population statistics. Service area analysis was performed using network analyst extension in ArcGIS 10.3v and results were evaluated for served and underserved areas and population. An accessibility tool was used to evaluate a set of potential destinations to determine which is the most accessible with the given population distribution. Findings of the study may contribute to facilitating the town planners and education authorities for understanding the existing patterns of school facilities. It is concluded that GIS and remote sensing can be effectively used in urban transport and facility planning.

Keywords: accessibility, geographic information system, landscan, worldview

Procedia PDF Downloads 314
1134 Accuracy/Precision Evaluation of Excalibur I: A Neurosurgery-Specific Haptic Hand Controller

Authors: Hamidreza Hoshyarmanesh, Benjamin Durante, Alex Irwin, Sanju Lama, Kourosh Zareinia, Garnette R. Sutherland

Abstract:

This study reports on a proposed method to evaluate the accuracy and precision of Excalibur I, a neurosurgery-specific haptic hand controller, designed and developed at Project neuroArm. Having an efficient and successful robot-assisted telesurgery is considerably contingent on how accurate and precise a haptic hand controller (master/local robot) would be able to interpret the kinematic indices of motion, i.e., position and orientation, from the surgeon’s upper limp to the slave/remote robot. A proposed test rig is designed and manufactured according to standard ASTM F2554-10 to determine the accuracy and precision range of Excalibur I at four different locations within its workspace: central workspace, extreme forward, far left and far right. The test rig is metrologically characterized by a coordinate measuring machine (accuracy and repeatability < ± 5 µm). Only the serial linkage of the haptic device is examined due to the use of the Structural Length Index (SLI). The results indicate that accuracy decreases by moving from the workspace central area towards the borders of the workspace. In a comparative study, Excalibur I performs on par with the PHANToM PremiumTM 3.0 and more accurate/precise than the PHANToM PremiumTM 1.5. The error in Cartesian coordinate system shows a dominant component in one direction (δx, δy or δz) for the movements on horizontal, vertical and inclined surfaces. The average error magnitude of three attempts is recorded, considering all three error components. This research is the first promising step to quantify the kinematic performance of Excalibur I.

Keywords: accuracy, advanced metrology, hand controller, precision, robot-assisted surgery, tele-operation, workspace

Procedia PDF Downloads 330
1133 Evaluation System of Spatial Potential Under Bridges in High Density Urban Areas of Chongqing Municipality and Applied Research on Suitability

Authors: Xvelian Qin

Abstract:

Urban "organic renewal" based on the development of existing resources in high-density urban areas has become the mainstream of urban development in the new era. As an important stock resource of public space in high-density urban areas, promoting its value remodeling is an effective way to alleviate the shortage of public space resources. However, due to the lack of evaluation links in the process of underpass space renewal, a large number of underpass space resources have been left idle, facing the problems of low space conversion efficiency, lack of accuracy in development decision-making, and low adaptability of functional positioning to citizens' needs. Therefore, it is of great practical significance to construct the evaluation system of under-bridge space renewal potential and explore the renewal mode. In this paper, some of the under-bridge spaces in the main urban area of Chongqing are selected as the research object. Through the questionnaire interviews with the users of the built excellent space under the bridge, three types of six levels and twenty-two potential evaluation indexes of "objective demand factor, construction feasibility factor and construction suitability factor" are selected, including six levels of land resources, infrastructure, accessibility, safety, space quality and ecological environment. The analytical hierarchy process and expert scoring method are used to determine the index weight, construct the potential evaluation system of the space under the bridge in high-density urban areas of Chongqing, and explore the direction of renewal and utilization of its suitability.

Keywords: space under bridge, potential evaluation, high density urban area, updated using

Procedia PDF Downloads 64
1132 Assessing the Efficiency of Sports Stadiums in India: An Explorative Study of Socio-Economic Sustainability

Authors: Shivam Adhikary

Abstract:

Sports stadiums are not merely public amenities for entertainment and recreation for a city. They are buildings with extremely high construction investment and running costs which holds the supreme responsibility of social integration, nation building and financial upliftment of the community apart from its primary motive of conducting and promotion of the sports. But the present scenario of sports performances at international events and growing physical inactivity among the youth in India show that the sports facilities are far behind in achieving these goals. A pilot study of Indira Gandhi Sports complex in Vijayawada, Andhra Pradesh gave an indication of underutilization of sports stadia in India. This probed a crying need for the assessment of the present usage and functioning of the major sports (non-cricketing) facilities within the country. This paper assesses the sustainability of stadiums built for national and international sporting (non-cricket) events in terms of sporting, socio-cultural and financial sustainability by mainly focusing on their usage in non-event days. The criteria for the assessment and comparison of the stadiums within the nation is done using World Stadium Index and GDI (Gross Domestic Income) while with international counterparts using WSI and GNI (Gross National Income). The pilot case of India Gandhi Sports complex in Vijayawada is further investigated for a deeper understanding of the present usage, the existing issues for its underutilization and the way-forward (at least a few) to reach its sustainable potential. The paper finally concludes with the discussion on whether sports stadiums are being utilized to its financial potential and if it is at par with its international counterparts.

Keywords: economic sustainability, social sustainability, sports infrastructure, stadium efficiency

Procedia PDF Downloads 184
1131 Prediction of California Bearing Ratio of a Black Cotton Soil Stabilized with Waste Glass and Eggshell Powder using Artificial Neural Network

Authors: Biruhi Tesfaye, Avinash M. Potdar

Abstract:

The laboratory test process to determine the California bearing ratio (CBR) of black cotton soils is not only overpriced but also time-consuming as well. Hence advanced prediction of CBR plays a significant role as it is applicable In pavement design. The prediction of CBR of treated soil was executed by Artificial Neural Networks (ANNs) which is a Computational tool based on the properties of the biological neural system. To observe CBR values, combined eggshell and waste glass was added to soil as 4, 8, 12, and 16 % of the weights of the soil samples. Accordingly, the laboratory related tests were conducted to get the required best model. The maximum CBR value found at 5.8 at 8 % of eggshell waste glass powder addition. The model was developed using CBR as an output layer variable. CBR was considered as a function of the joint effect of liquid limit, plastic limit, and plastic index, optimum moisture content and maximum dry density. The best model that has been found was ANN with 5, 6 and 1 neurons in the input, hidden and output layer correspondingly. The performance of selected ANN has been 0.99996, 4.44E-05, 0.00353 and 0.0067 which are correlation coefficient (R), mean square error (MSE), mean absolute error (MAE) and root mean square error (RMSE) respectively. The research presented or summarized above throws light on future scope on stabilization with waste glass combined with different percentages of eggshell that leads to the economical design of CBR acceptable to pavement sub-base or base, as desired.

Keywords: CBR, artificial neural network, liquid limit, plastic limit, maximum dry density, OMC

Procedia PDF Downloads 176
1130 Comparative Analysis of Glycated Hemoglobin (hba1c) Between HPLC and Immunoturbidimetry Method in Type II Diabetes Mellitus Patient

Authors: Intanri Kurniati, Raja Iqbal Mulya Harahap, Agustyas Tjiptaningrum, Reni Zuraida

Abstract:

Background: Diabetes mellitus is still increasing and has become a health and social burden in the world. It is known that glycation among various proteins is increased in diabetic patients compared with non-diabetic subjects. Some of these glycated proteins are suggested to be involved in the development and progression of chronic diabetic complications. Among these glycated proteins, glycated hemoglobin (HbA1C) is commonly used as the gold standard index of glycemic control in the clinical setting. HbA1C testing has some methods, and the most commonly used is immunoturbidimetry. This research aimed to compare the HbA1c level between immunoturbidimetry and HbA1C level in T2DM patients. Methods: This research involves 77 patients from Abd Muluk Hospital Bandar Lampung; the patient was asked for consent in this research, then underwent phlebotomy to be tested for HbA1C; the sample was then examined for HbA1C with Turbidimetric Inhibition Immunoassay (TINIA) and High-Performance Liquid Chromatography (HPLC) method. Result: Mean± SD of the samples with the TINIA method was 9.2±1,2; meanwhile, the level HbA1C with the HPLC method is 9.6±1,2. The t-test showed no significant difference between the group subjects. (p<0.05). It was proposed that the two methods have high suitability in testing, and both are eligibly used for the patient. Discussion: There was no significant difference among research subjects, indicating that the high conformity of the two methods is suitable to be used for monitoring patients clinically. Conclusion: There is increasing in HbA1C level in a patient with T2DM measured with HPLC and or Turbidimetric Inhibition Immunoassay (TINIA) method, and there were no significant differences among those methods.

Keywords: diabetes mellitus, glycated albumin, HbA1C, HPLC, immunoturbidimetry

Procedia PDF Downloads 91
1129 Optimization, Characterization and Stability of Trachyspermum copticum Essential Oil Loaded in Niosome Nanocarriers

Authors: Mohadese Hashemi, Elham Akhoundi Kharanaghi, Fatemeh Haghiralsadat, Mojgan Yazdani, Omid Javani, Mahboobe Sharafodini, Davood Rajabi

Abstract:

Niosomes are non-ionic surfactant vesicles in aqueous media resulting in closed bilayer structures that can be used as carriers of hydrophilic and hydrophobic compounds. The use of niosomes for encapsulation of essential oils (EOs) is an attractive new approach to overcome their physicochemical stability concerns include sensibility to oxygen, light, temperature, and volatility, and their reduced bioavailability which is due to low solubility in water. EOs are unstable and fragile volatile compounds which have strong interest in pharmaceutical due to their medicinal properties such as antiviral, anti-inflammatory, antifungal, and antioxidant activities without side effects. Trachyspermum copticum (ajwain) is an annual aromatic plant with important medicinal properties that grows widely around Mediterranean region and south-west Asian countries. The major components of the ajwain oil were reported as thymol, γ-terpinene, p-cymene, and carvacrol which provide antimicrobial and antioxidant activity. The aim of this work was to formulate ajwain essential oil-loaded niosomes to improve water solubility of natural product and evaluate its physico-chemical features and stability. Ajwain oil was obtained through steam distillation using a clevenger-type apparatus and GC/MS was applied to identify the main components of the essential oil. Niosomes were prepared by using thin film hydration method and nanoparticles were characterized for particle size, dispersity index, zeta potential, encapsulation efficiency, in vitro release, and morphology.

Keywords: trachyspermum copticum, ajwain, niosome, essential oil, encapsulation

Procedia PDF Downloads 473
1128 Comparison of Computerized Dynamic Posturography and Functional Head Impulse Test Scores after of Hatha Yoga Practice and Resistance-Based Aerobic Exercise in Adult Female Yoga Practitioners

Authors: Çağla Aras, Kübra Bi̇nay, Aysberg Şamil önlü, Mine Baydan Aran, Dicle Aras

Abstract:

The purpose of the present research was to investigate the acute effects of 30-min hatha yoga and 30-min resistance-based aerobic exercise (RBAE) on computerized dynamic posturography (CDP) and functional head impulse test (fHIT) scores in adult female yoga practitioners. To reach this aim, ten participants executed CDP and fHIT three times in total: at rest, after yoga, and after RBAE. The yoga practice lasted a total of 30 minutes, including 25 min of asanas and 5 minutes of savasana. RBAE lasted a total of 30 minutes with an intensity of 70-75% of the heart rate reserve method. When the results were examined, no change was observed in any parameters of the fHIT scores due to resting or exercise implementation. On the contrary, some changes were observed in CDP test results depending on the type of exercise. The post-RBAE somatosensory and visual systems values were higher than resting (p<0.05). The composite balance score derived after RBAE was found to be improved when compared to post-yoga and resting values (p<0.01). Lastly, the post-RBAE vestibular system score was found to be statistically significantly higher than the post-Yoga values. In addition, it was observed that body composition parameters, especially decreasing BW, LBM, PBF, MBF and TBW, were associated with improved postural stability values. According to the results, it can be stated that neither hatha yoga nor resistance-based aerobic exercise has an acute effect on functional vestibulo-ocular reflex. In addition, although there was no change in balance level after yoga, it was observed that RBAE performed at 70-75% of the heart rate reserve and for 30 minutes had positive acute effects on postural stability and balance.

Keywords: hatha yoga, resistance training, aerobic training, high intensity training, computerized dynamic posturography, functional head impulse test

Procedia PDF Downloads 41
1127 High Aspect Ratio Sio2 Capillary Based On Silicon Etching and Thermal Oxidation Process for Optical Modulator

Authors: Nguyen Van Toan, Suguru Sangu, Tetsuro Saito, Naoki Inomata, Takahito Ono

Abstract:

This paper presents the design and fabrication of an optical window for an optical modulator toward image sensing applications. An optical window consists of micrometer-order SiO2 capillaries (porous solid) that can modulate transmission light intensity by moving the liquid in and out of porous solid. A high optical transmittance of the optical window can be achieved due to refractive index matching when the liquid is penetrated into the porous solid. Otherwise, its light transmittance is lower because of light reflection and scattering by air holes and capillary walls. Silicon capillaries fabricated by deep reactive ion etching (DRIE) process are completely oxidized to form the SiO2 capillaries. Therefore, high aspect ratio SiO2 capillaries can be achieved based on silicon capillaries formed by DRIE technique. Large compressive stress of the oxide causes bending of the capillary structure, which is reduced by optimizing the design of device structure. The large stress of the optical window can be released via thin supporting beams. A 7.2 mm x 9.6 mm optical window area toward a fully integrated with the image sensor format is successfully fabricated and its optical transmittance is evaluated with and without inserting liquids (ethanol and matching oil). The achieved modulation range is approximately 20% to 35% with and without liquid penetration in visible region (wavelength range from 450 nm to 650 nm).

Keywords: thermal oxidation process, SiO2 capillaries, optical window, light transmittance, image sensor, liquid penetration

Procedia PDF Downloads 477
1126 Factors Associated with Overweight and Obesity among Recipients of Antiretroviral Therapy at HIV Clinics in Botswana

Authors: Jose G. Tshikuka, Goabaone Rankgoane-Pono, Mgaywa G. M. D. Magafu, Julius C. Mwita, Tiny Masupe, Fortunat M. Kandanda, Shimeles G. Hamda, Roy Tapera, Mooketsi Molefi, John T. Tlhakanelo

Abstract:

Background: Factors associated with overweight and obesity among antiretroviral therapy (ART) recipients have not been sufficiently studied in Botswana. We aimed to study (i) the prevalence and trends in overweight/obesity by duration of exposure to ART among recipients, (ii) changes in body mass index (BMI) categories among recipients before ART initiation (BMI-1) and after ART initiation (BMI-2), (iii) associations between ART and overweight/obesity and (iv) factors associated with BMI changes among ART recipients. Methods: A 12 years retrospective record-based review was conducted. Factors potentially associated with BMI change among patients after at least three years of ART exposure were examined using multiple regression model. Adjusted odds ratios (AOR) and their 95% confidence intervals (CIs) were computed. ART regimens, duration of exposure to ART, and recipients’ demographic and biomedical characteristics including the presence or absence of diabetes mellitus related comorbidities (DRC) were investigated as potential factors associated with overweight/obesity. Results: Twenty-nine percent of recipients were overweight, 16.6% had obesity of whom 2.4% were morbidly-obese at the last clinic visit. Overweight/obesity recipients were more likely to be female, to have DRC and less likely to have nadir CD4 count or CD4 count between 201 – 249 cells/mm³. Neither the first-line nor the second-, third-line ART regimens predicted overweight/obesity more than the other and neither did the duration of exposure to ART. No significant linear trends were observed in the prevalence of overweight/obesity by the duration of exposure to ART. Conclusions: These results indicate that overweight/obesity seen among ART recipients is not directly induced by ART. ART used CD4 and/or DRC pathway to induce overweight/obesity seen among recipients; suggesting that, weight gain documented herein is likely a reflection of improved health status that mirrors trends in the general population or a DRC related effect. Weight management programs may be important components of HIV care.

Keywords: overweight/obesity, recipients of antiretroviral therapy, HIV/AIDS, Botswana

Procedia PDF Downloads 149
1125 Optimization of a Bioremediation Strategy for an Urban Stream of Matanza-Riachuelo Basin

Authors: María D. Groppa, Andrea Trentini, Myriam Zawoznik, Roxana Bigi, Carlos Nadra, Patricia L. Marconi

Abstract:

In the present work, a remediation bioprocess based on the use of a local isolate of the microalgae Chlorella vulgaris immobilized in alginate beads is proposed. This process was shown to be effective for the reduction of several chemical and microbial contaminants present in Cildáñez stream, a water course that is part of the Matanza-Riachuelo Basin (Buenos Aires, Argentina). The bioprocess, involving the culture of the microalga in autotrophic conditions in a stirred-tank bioreactor supplied with a marine propeller for 6 days, allowed a significant reduction of Escherichia coli and total coliform numbers (over 95%), as well as of ammoniacal nitrogen (96%), nitrates (86%), nitrites (98%), and total phosphorus (53%) contents. Pb content was also significantly diminished after the bioprocess (95%). Standardized cytotoxicity tests using Allium cepa seeds and Cildáñez water pre- and post-remediation were also performed. Germination rate and mitotic index of onion seeds imbibed in Cildáñez water subjected to the bioprocess was similar to that observed in seeds imbibed in distilled water and significantly superior to that registered when untreated Cildáñez water was used for imbibition. Our results demonstrate the potential of this simple and cost-effective technology to remove urban-water contaminants, offering as an additional advantage the possibility of an easy biomass recovery, which may become a source of alternative energy.

Keywords: bioreactor, bioremediation, Chlorella vulgaris, Matanza-Riachuelo Basin, microalgae

Procedia PDF Downloads 235
1124 Absorption Kinetic and Tensile Mechanical Properties of Swollen Elastomer/Carbon Black Nanocomposites using Typical Solvents

Authors: F. Elhaouzi, H. Lahlali, M. Zaghrioui, I. El Aboudi A. BelfKira, A. Mdarhri

Abstract:

The effect of physico chemical properties of solvents on the transport process and mechanical properties in elastomeric nano composite materials is reported. The investigated samples are formed by a semi-crystalline ethylene-co-butyl acrylate polymer filled with hard spherical carbon black (CB) nano particles. The swelling behavior was studied by immersion the dried samples in selected solvents at room temperature during 2 days. For this purpose, two chemical compounds methyl derivatives of aromatic hydrocarbons of benzene, i.e. toluene and xylene, are used to search for the mass and molar volume dependence on the absorption kinetics. Mass gain relative to the mass of dry material at specific times was recorded to probe the absorption kinetics. The transport of solvent molecules in these filled elastomeric composites is following a Fickian diffusion mechanism. Additionally, the swelling ratio and diffusivity coefficient deduced from the Fickian law are found to decrease with the CB concentration. These results indicate that the CB nano particles increase the effective path length for diffusion and consequently limit the absorption of the solvent by occupation free volumes in the material. According to physico chemical properties of the two used solvents, it is found that the diffusion is more important for the toluene molecules solvent due to their low values of the molecular weight and volume molar compared to those for the xylene. Differential Scanning Calorimetry (DSC) and X-ray photo electron (XPS) were also used to probe the eventual change in the chemical composition for the swollen samples. Mechanically speaking, the stress-strain curves of uniaxial tensile tests pre- and post- swelling highlight a remarkably decrease of the strength and elongation at break of the swollen samples. This behavior can be attributed to the decrease of the load transfer density between the matrix and the CB in the presence of the solvent. We believe that the results reported in this experimental investigation can be useful for some demanding applications e.g. tires, sealing rubber.

Keywords: nanocomposite, absorption kinetics, mechanical behavior, diffusion, modelling, XPS, DSC

Procedia PDF Downloads 343
1123 Creation of an Integrated Development Environment to Assist and Optimize the Learning the Languages C and C++

Authors: Francimar Alves, Marcos Castro, Marllus Lustosa

Abstract:

In the context of the teaching of computer programming, the choice of tool to use is very important in the initiation and continuity of learning a programming language. The literature tools do not always provide usability and pedagogical dynamism clearly and accurately for effective learning. This hypothesis implies fall in productivity and difficulty of learning a particular programming language by students. The integrated development environments (IDEs) Dev-C ++ and Code :: Blocks are widely used in introductory courses for undergraduate courses in Computer Science for learning C and C ++ languages. However, after several years of discontinuity maintaining the source code of Dev-C ++ tool, the continued use of the same in the teaching and learning process of the students of these institutions has led to difficulties, mainly due to the lack of update by the official developers, which resulted in a sequence of problems in using it on educational settings. Much of the users, dissatisfied with the IDE Dev-C ++, migrated to Code :: Blocks platform targeting the more dynamic range in the learning process of the C and C ++ languages. Nevertheless, there is still the need to create a tool that can provide the resources of most IDE's software development literature, however, more interactive, simple, accurate and efficient. This motivation led to the creation of Falcon C ++ tool, IDE that brings with features that turn it into an educational platform, which focuses primarily on increasing student learning index in the early disciplines of programming and algorithms that use the languages ​​C and C ++ . As a working methodology, a field research to prove the truth of the proposed tool was used. The test results and interviews with entry-level students and intermediate in a postsecondary institution gave basis for the composition of this work, demonstrating a positive impact on the use of the tool in teaching programming, showing that the use of Falcon C ++ software is beneficial in the teaching process of the C and C ++ programming languages.

Keywords: ide, education, learning, development, language

Procedia PDF Downloads 432
1122 The Relationship between Renewable Energy, Real Income, Tourism and Air Pollution

Authors: Eyup Dogan

Abstract:

One criticism of the energy-growth-environment literature, to the best of our knowledge, is that only a few studies analyze the influence of tourism on CO₂ emissions even though tourism sector is closely related to the environment. The other criticism is the selection of methodology. Panel estimation techniques that fail to consider both heterogeneity and cross-sectional dependence across countries can cause forecasting errors. To fulfill the mentioned gaps in the literature, this study analyzes the impacts of real GDP, renewable energy and tourism on the levels of carbon dioxide (CO₂) emissions for the top 10 most-visited countries around the world. This study focuses on the top 10 touristic (most-visited) countries because they receive about the half of the worldwide tourist arrivals in late years and are among the top ones in 'Renewables Energy Country Attractiveness Index (RECAI)'. By looking at Pesaran’s CD test and average growth rates of variables for each country, we detect the presence of cross-sectional dependence and heterogeneity. Hence, this study uses second generation econometric techniques (cross-sectionally augmented Dickey-Fuller (CADF), and cross-sectionally augmented IPS (CIPS) unit root test, the LM bootstrap cointegration test, and the DOLS and the FMOLS estimators) which are robust to the mentioned issues. Therefore, the reported results become accurate and reliable. It is found that renewable energy mitigates the pollution whereas real GDP and tourism contribute to carbon emissions. Thus, regulatory policies are necessary to increase the awareness of sustainable tourism. In addition, the use of renewable energy and the adoption of clean technologies in tourism sector as well as in producing goods and services play significant roles in reducing the levels of emissions.

Keywords: air pollution, tourism, renewable energy, income, panel data

Procedia PDF Downloads 173
1121 The Development of E-Commerce in Mexico: An Econometric Analysis

Authors: Alma Lucero Ortiz, Mario Gomez

Abstract:

Technological advances contribute to the well-being of humanity by allowing man to perform in a more efficient way. Technology offers tangible advantages to countries with the adoption of information technologies, communication, and the Internet in all social and productive sectors. The Internet is a networking infrastructure that allows the communication of people throughout the world, exceeding the limits of time and space. Nowadays the internet has changed the way of doing business leading to a digital economy. In this way, e-commerce has emerged as a commercial transaction conducted over the Internet. For this inquiry e-commerce is seen as a source of economic growth for the country. Thereby, these research aims to answer the research question, which are the main variables that have affected the development of e-commerce in Mexico. The research includes a period of study from 1990 to 2017. This inquiry aims to get insight on how the independent variables influence the e-commerce development. The independent variables are information infrastructure construction, urbanization level, economic level, technology level, human capital level, educational level, standards of living, and price index. The results suggest that the independent variables have an impact on development of the e-commerce in Mexico. The present study is carried out in five parts. After the introduction, in the second part, a literature review about the main qualitative and quantitative studies to measure the variables subject to the study is presented. After, an empirical study is applied through time series data, and to process the data an econometric model is performed. In the fourth part, the analysis and discussion of results are presented, and finally, some conclusions are included.

Keywords: digital economy, e-commerce, econometric model, economic growth, internet

Procedia PDF Downloads 223
1120 Development of Site-Specific Colonic Drug Delivery System (Nanoparticles) of Chitosan Coated with pH Sensitive Polymer for the Management of Colonic Inflammation

Authors: Pooja Mongia Raj, Rakesh Raj, Alpana Ram

Abstract:

Background: The use of multiparticulate drug delivery systems in preference to single unit dosage forms for colon targeting purposes dates back to 1985 when Hardy and co-workers showed that multiparticulate systems enabled the drug to reach the colon quickly and were retained in the ascending colon for a relatively long period of time. Methods: Site-specific colonic drug delivery system (nanoparticles) of 5-ASA were prepared and coated with pH sensitive polymer. Chitosan nanoparticles (CTNP) bearing 5-Amino salicylic acid (5-ASA) were prepared, by ionotropic gelation method. Nanoparticulate dosage form consisting of a hydrophobic core enteric coated with pH-dependent polymer Eudragit S-100 by solvent evaporation method, for the effective delivery of drug to the colon for treatment of ulcerative colitis. Results: The mean diameter of CTNP and ECTNP formulations were 159 and 661 nm, respectively. Also optimum value of polydispersity index was found to be 0.249 [count rate (kcps) was 251.2] and 0.170 [count rate (kcps) was 173.9] was obtained for both the formulations respectively. Conclusion: CTNP and Eudragit chitosan nanoparticles (ECTNP) was characterized for shape and surface morphology by scanning electron microscopy (SEM) appeared to be spherical in shape. The in vitro drug release was investigated using USP dissolution test apparatus in different simulated GIT fluids showed promising release. In vivo experiments are in further proceeding for fruitful results.

Keywords: colon targeting, nanoparticles, polymer, 5-amino salicylic acid, edragit

Procedia PDF Downloads 485
1119 Flexural Properties of Carbon/Polypropylene Composites: Influence of Matrix Forming Polypropylene in Fiber, Powder, and Film States

Authors: Vijay Goud, Ramasamy Alagirusamy, Apurba Das, Dinesh Kalyanasundaram

Abstract:

Thermoplastic composites render new opportunities as effective processing technology while crafting newer complications into processing. One of the notable challenges is in achieving thorough wettability that is significantly deterred by the high viscosity of the long molecular chains of the thermoplastics. As a result of high viscosity, it is very difficult to impregnate the resin into a tightly interlaced textile structure to fill the voids present in the structure. One potential solution to the above problem, is to pre-deposit resin on the fiber, prior to consolidation. The current study compares DREF spinning, powder coating and film stacking methods of predeposition of resin onto fibers. An investigation into the flexural properties of unidirectional composites (UDC) produced from blending of carbon fiber and polypropylene (PP) matrix in varying forms of fiber, powder and film are reported. Dr. Ernst Fehrer (DREF) yarns or friction spun hybrid yarns were manufactured from PP fibers and carbon tows. The DREF yarns were consolidated to yield unidirectional composites (UDCs) referred to as UDC-D. PP in the form of powder was coated on carbon tows by electrostatic spray coating. The powder-coated towpregs were consolidated to form UDC-P. For the sake of comparison, a third UDC referred as UDC-F was manufactured by the consolidation of PP films stacked between carbon tows. The experiments were designed to yield a matching fiber volume fraction of about 50 % in all the three UDCs. A comparison of mechanical properties of the three composites was studied to understand the efficiency of matrix wetting and impregnation. Approximately 19% and 68% higher flexural strength were obtained for UDC-P than UDC-D and UDC-F respectively. Similarly, 25% and 81% higher modulus were observed in UDC-P than UDC-D and UDC-F respectively. Results from micro-computed tomography, scanning electron microscopy, and short beam tests indicate better impregnation of PP matrix in UDC-P obtained through electrostatic spray coating process and thereby higher flexural strength and modulus.

Keywords: DREF spinning, film stacking, flexural strength, powder coating, thermoplastic composite

Procedia PDF Downloads 217
1118 Attitudes of Secondary School Students towards Science and Technical Education in Yauri Metropolis Kebbi State, Nigeria

Authors: Ibrahim Alhassan Libata

Abstract:

This study was carried out to assess attitude of secondary school students towards science and technical education in Yauri metropolis, Kebbi State, Nigeria. The population of the study was 200. Proportionate random sampling method was used in selecting 132 as sample size. Science and technical education is the most powerful forces for change in the world today, and students who hope to have a hand in shaping a better future must participate for their advancements. Four Null hypotheses were generated to guide the conduct of the study, questionnaire was the only instrument used in the study; the instrument was subjected to test-retest reliability. The reliability index of the instrument was 0.69. Overall scores of the Students were analyzed and a mean score was determined, the mean score of students was 85. There were no significant differences between the attitudes of male and female students towards science and technical education. The results also revealed that there was significant difference between the attitude of boding and day school students towards science and technical education, personality constraints of students is one factor militating against the participation of students in science and technical education, socio-economic status of the parents over the years have been the dominant factor of student’s inadequate representation in the field of science and technical education. Based on the findings of this study, the researcher recommended that teachers should motivate students, which they can do through their teaching styles and by showing them the relevance of the learning topics to their everyday lives. Government and the school management should create the learning environment that helps motivate students not only to come to classes but also want to learn and enjoy learning science and technical education, establishment of more Science and Technical Colleges education, more Public enlightenment campaigns to motivate parents and the entire community to support their children in studying science and technical education.

Keywords: attitude, students, science, Yauri

Procedia PDF Downloads 235
1117 The Relationship between Self-Care Behaviour and Quality of Life Among Heart Failure Patients in Jakarta, Indonesia

Authors: Shedy Maharani Nariswari, Prima Agustia Nova, I. Made Kariasa

Abstract:

Background. Heart Failure (HF) is a chronic and progressive condition associated with significant morbidity, mortality, health care expenditures, and a high readmission rate over the years. Self‐care is essential to manage chronic heart failure in the long term, and it is related to better outcomes and can enhance the quality of life. Objective. The aims of this study were to describe the relationship between self-care behavior and quality of life among heart failure patients in East Jakarta, Indonesia. Methods. This study used a correlational-descriptive design with a cross-sectional study, the sampling method used purposive sampling method. Self-care was measured using Self-care Heart Failure Index version 6.2, and quality of life was measured using The Minnesota Living with Heart Failure. Pearson correlation and Spearman-rho correlations are used to analyze the data. Results. We recruited 103 patients with HF in both outpatient and inpatient ward: mean age 59.26 ± 11.643 years, 63.1% male. Patients with higher levels of education were associated with higher self-care maintenance (p= 0.007). The patient's average quality of life is quite high, with a score of 72,07 ± 16,89. There were a significant relationship among self-care maintenance (r=0,305, p=0,001), self-care management (r=0,330, p=0,001), and self-care confidence (r=0,335, p=0,001) towards the quality of life. Most participants have inadequate self-care maintenance, self-care management, and self-care confidence (score < 70), while the score of quality of life is categorized as poor. Conclusion. The self-care behaviors were limited among patients living with HF in Indonesia yet was associated with better quality of life. It is necessary to promote health related to knowledge and adherence to self-care behavior so that it can improve the quality of life of heart failure patients. This study can be used as a reference to promote self-care among patients with heart failure, it can help to enhance their quality of life.

Keywords: heart failure, self-care maintenance, self-care management, self-care confidence, quality of life

Procedia PDF Downloads 96
1116 Effect of Climate Change on Nutritional Status of Women in Nigeria

Authors: Onu Theresa Chinyere

Abstract:

The study evaluates the perceived effect of climate change on nutritional status of women in Nigeria. Five research questions and two hypotheses were formulated to guide the study. The study adopted a survey and experimental study research design. One thousand two hundred and fifty one (1,250) respondents were selected from different State in Nigeria using multistage sampling technique. The instruments used to collect data were questionnaire and personal interview on socio economic characteristics of respondents, while Anthropometric data (height and weight) were also used. The data was analyzed using t-test statistic, decided at 50% level of significance. The study found that most states in Nigeria experience high winds, warmer and frequent hot days and night over most land areas, droughts and tides during climate change events. The respondent unanimously agree that climate change causes reduction in food yields, decline in food availability/supply, negatively affecting soil quality, carbon fertilization, decreases flexibilities in technology choices to strengthen food production. The Anthropometric analysis shows that out of 1250 women sampled, 560 (44.8%) maintain normal weight, while 405 (32.40%) women were found to be underweight, since their body mass index is less that 18.5. There were few cases of obesity among the surveyed women since only 80 out of 1250 which represent 6.4% of the women were obese. Bases on the findings, the following recommendations were made-local fertilizer should be encouraged to boost foods yield especially during climate change: women should imbibe the culture of preservation or reservoir that will help in mitigating the effects of climate on food intake and nutritional status, especially during the crisis period, among others.

Keywords: climate change, nutrition anthropometric analysis, obesity culture, environment and women among others

Procedia PDF Downloads 414
1115 Functionality and Application of Rice Bran Protein Hydrolysates in Oil in Water Emulsions: Their Stabilities to Environmental Stresses

Authors: R. Charoen, S. Tipkanon, W. Savedboworn, N. Phonsatta, A. Panya

Abstract:

Rice bran protein hydrolysates (RBPH) were prepared from defatted rice bran of two different Thai rice cultivars (Plai-Ngahm-Prachinburi; PNP and Khao Dok Mali 105; KDM105) using an enzymatic method. This research aimed to optimize enzyme-assisted protein extraction. In addition, the functional properties of RBPH and their stabilities to environmental stresses including pH (3 to 8), ionic strength (0 mM to 500 mM) and the thermal treatment (30 °C to 90 °C) were investigated. Results showed that enzymatic process for protein extraction of defatted rice bran was as follows: enzyme concentration 0.075 g/ 5 g of protein, extraction temperature 50 °C and extraction time 4 h. The obtained protein hydrolysate powders had a degree of hydrolysis (%) of 21.05% in PNP and 19.92% in KDM105. The solubility of protein hydrolysates at pH 4-6 was ranged from 27.28-38.57% and 27.60-43.00% in PNP and KDM105, respectively. In general, antioxidant activities indicated by total phenolic content, FRAP, ferrous ion-chelating (FIC), and 2,2’-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) of KDM105 had higher than PNP. In terms of functional properties, the emulsifying activity index (EAI) was was 8.78 m²/g protein in KDM105, whereas PNP was 5.05 m²/g protein. The foaming capacity at 5 minutes (%) was 47.33 and 52.98 in PNP and KDM105, respectively. Glutamine, Alanine, Valine, and Leucine are the major amino acid in protein hydrolysates where the total amino acid of KDM105 gave higher than PNP. Furthermore, we investigated environmental stresses on the stability of 5% oil in water emulsion (5% oil, 10 mM citrate buffer) stabilized by RBPH (3.5%). The droplet diameter of emulsion stabilized by KDM105 was smaller (d < 250 nm) than produced by PNP. For environmental stresses, RBPH stabilized emulsions were stable at pH around 3 and 5-6, at high salt (< 400 mM, pH 7) and at temperatures range between 30-50°C.

Keywords: functional properties, oil in water emulsion, protein hydrolysates, rice bran protein

Procedia PDF Downloads 200
1114 Autonomic Nervous System Changes Associated with Rheumatoid Arthritis: Clinical and Electrophysiological Study

Authors: Emmanuel Kamal Aziz Saba, Hussein Al-Moghazy Sultan

Abstract:

The aim of this study was to evaluate clinically and electro physiologically the autonomic nervous system changes associated with rheumatoid arthritis (RA). The present study included 25 patients with RA [22 women (88%)] and 30 apparently healthy control subjects [27 women (90%)]. A thorough clinical examination was carried out. Disease activity and functional disability were assessed. Tests for assessment of autonomic functions include active and passive orthostatic stress tests, and sympathetic skin response (SSR). The presence of abnormality in 2 tests or more was a clue for the presence of autonomic neuropathy (AN). Sural sensory nerve conduction study and posterior tibial motor nerve conduction study were done. There was a statistically significant decrease in standing systolic and diastolic blood pressure (BP) components of the active orthostatic stress test and SSR amplitude as well as statistically significant prolongation of SSR latency of RA patients when compared to control. Three patients (12%) had clinical symptoms suggestive of AN; increased to 14 patients (56 %) when orthostatic stress tests and SSR were utilized. There were no statistically significant differences between patients with different disease activity score 28 with 4 variables grades of RA activity and SSR latency and amplitude. There were no statistically significant differences between patients with different Stanford Health Assessment Questionnaire Disability Index grades of RA functional disability and SSR latency and amplitude. In conclusion, autonomic neuropathy is a common extra-articular manifestation of RA affecting sympathetic and parasympathetic fibers.

Keywords: autonomic neuropathy, orthostatic stress test, rheumatoid arthritis, sympathetic skin response

Procedia PDF Downloads 347
1113 Band Characterization and Development of Hyperspectral Indices for Retrieving Chlorophyll Content

Authors: Ramandeep Kaur M. Malhi, Prashant K. Srivastava, G.Sandhya Kiran

Abstract:

Quantitative estimates of foliar biochemicals, namely chlorophyll content (CC), serve as key information for the assessment of plant productivity, stress, and the availability of nutrients. This also plays a critical role in predicting the dynamic response of any vegetation to altering climate conditions. The advent of hyperspectral data with an enhanced number of available wavelengths has increased the possibility of acquiring improved information on CC. Retrieval of CC is extensively carried through well known spectral indices derived from hyperspectral data. In the present study, an attempt is made to develop hyperspectral indices by identifying optimum bands for CC estimation in Butea monosperma (Lam.) Taub growing in forests of Shoolpaneshwar Wildlife Sanctuary, Narmada district, Gujarat State, India. 196 narrow bands of EO-1 Hyperion images were screened, and the best optimum wavelength from blue, green, red, and near infrared (NIR) regions were identified based on the coefficient of determination (R²) between band reflectance and laboratory estimated CC. The identified optimum wavelengths were then employed for developing 12 hyperspectral indices. These spectral index values and CC values were then correlated to investigate the relation between laboratory measured CC and spectral indices. Band 15 of blue range and Band 22 of green range, Band 40 of the red region, and Band 79 of NIR region were found to be optimum bands for estimating CC. The optimum band based combinations on hyperspectral data proved to be the most effective indices for quantifying Butea CC with NDVI and TVI identified as the best (R² > 0.7, p < 0.01). The study demonstrated the significance of band characterization in the development of the best hyperspectral indices for the chlorophyll estimation, which can aid in monitoring the vitality of forests.

Keywords: band, characterization, chlorophyll, hyperspectral, indices

Procedia PDF Downloads 141
1112 [Keynote Talk]: Water Resources Vulnerability Assessment to Climate Change in a Semi-Arid Basin of South India

Authors: K. Shimola, M. Krishnaveni

Abstract:

This paper examines vulnerability assessment of water resources in a semi-arid basin using the 4-step approach. The vulnerability assessment framework is developed to study the water resources vulnerability which includes the creation of GIS-based vulnerability maps. These maps represent the spatial variability of the vulnerability index. This paper introduces the 4-step approach to assess vulnerability that incorporates a new set of indicators. The approach is demonstrated using a framework composed of a precipitation data for (1975–2010) period, temperature data for (1965–2010) period, hydrological model outputs and the water resources GIS data base. The vulnerability assessment is a function of three components such as exposure, sensitivity and adaptive capacity. The current water resources vulnerability is assessed using GIS based spatio-temporal information. Rainfall Coefficient of Variation, monsoon onset and end date, rainy days, seasonality indices, temperature are selected for the criterion ‘exposure’. Water yield, ground water recharge, evapotranspiration (ET) are selected for the criterion ‘sensitivity’. Type of irrigation and storage structures are selected for the criterion ‘Adaptive capacity’. These indicators were mapped and integrated in GIS environment using overlay analysis. The five sub-basins, namely Arjunanadhi, Kousiganadhi, Sindapalli-Uppodai and Vallampatti Odai, fall under medium vulnerability profile, which indicates that the basin is under moderate stress of water resources. The paper also explores prioritization of sub-basinwise adaptation strategies to climate change based on the vulnerability indices.

Keywords: adaptive capacity, exposure, overlay analysis, sensitivity, vulnerability

Procedia PDF Downloads 306
1111 Detailed Investigation of Thermal Degradation Mechanism and Product Characterization of Co-Pyrolysis of Indian Oil Shale with Rubber Seed Shell

Authors: Bhargav Baruah, Ali Shemsedin Reshad, Pankaj Tiwari

Abstract:

This work presents a detailed study on the thermal degradation kinetics of co-pyrolysis of oil shale of Upper Assam, India with rubber seed shell, and lab-scale pyrolysis to investigate the influence of pyrolysis parameters on product yield and composition of products. The physicochemical characteristics of oil shale and rubber seed shell were studied by proximate analysis, elemental analysis, Fourier transform infrared spectroscopy and X-ray diffraction. The physicochemical study showed the mixture to be of low moisture, high ash, siliceous, sour with the presence of aliphatic, aromatic, and phenolic compounds. The thermal decomposition of the oil shale with rubber seed shell was studied using thermogravimetric analysis at heating rates of 5, 10, 20, 30, and 50 °C/min. The kinetic study of the oil shale pyrolysis process was performed on the thermogravimetric (TGA) data using three model-free isoconversional methods viz. Friedman, Flynn Wall Ozawa (FWO), and Kissinger Akahira Sunnose (KAS). The reaction mechanisms were determined using the Criado master plot. The understanding of the composition of Indian oil shale and rubber seed shell and pyrolysis process kinetics can help to establish the experimental parameters for the extraction of valuable products from the mixture. Response surface methodology (RSM) was employed usinf central composite design (CCD) model to setup the lab-scale experiment using TGA data, and optimization of process parameters viz. heating rate, temperature, and particle size. The samples were pre-dried at 115°C for 24 hours prior to pyrolysis. The pyrolysis temperatures were set from 450 to 650 °C, at heating rates of 2 to 20°C/min. The retention time was set between 2 to 8 hours. The optimum oil yield was observed at 5°C/min and 550°C with a retention time of 5 hours. The pyrolytic oil and gas obtained at optimum conditions were subjected to characterization using Fourier transform infrared spectroscopy (FT-IR) gas chromatography and mass spectrometry (GC-MS) and nuclear magnetic resonance spectroscopy (NMR).

Keywords: Indian oil shale, rubber seed shell, co-pyrolysis, isoconversional methods, gas chromatography, nuclear magnetic resonance, Fourier transform infrared spectroscopy

Procedia PDF Downloads 134
1110 Impact of an Exercise Program on Physical Fitness of a Candidate to Naval Academy: A Case Study

Authors: Ricardo Chaves, Carlos Vasconcelos

Abstract:

Candidates to join the Naval Academy have to take a set of physical tests, which is crucial for a high level of physical fitness. Thus, the planning of physical exercises for candidates to the Naval School must take into account the improvement of their physical fitness. The aim of this study was to investigate the impact of a 6-month exercise program to improve the physical fitness of an individual who will apply for the Naval Academy. This was a non-experimental pre-post-evaluation study. The patient was male, had 18 years old, and a body mass index of 21.1 kg.m². The patient participated in a 6-month aerobic and strength exercise program (3 sessions per week, 75 minutes duration each session). Physical fitness tests were performed according to the physical fitness requirements for entry into the Naval academy (muscle strength [maximum number of lifts and maximum number of sit-ups for 1 minute]; aerobic fitness [2.4 km run and 200 m swimming test]) before (baseline) and after the exercise intervention (6 months). Regarding muscle strength, in the abdominal test, the improvements between the pre-test (39 abdominals.) and post-test (61 abdominals) were 56.4%. For elevations, there was an increase in its number by 150% between the pre-test (4 elevations) and post-test (10 elevations). With regard to aerobic fitness, in the 2.4 km race, there was an evolution of 32.0% between the pre-test (16.46 min.) and the post-test (12.42 min.). For the 200-meter swimming test, there was a negative variation of 2% between the pre-test (2.25 min.) and post-test (2.28 min). A 6-month aerobic and strength exercise program leads to a positive evolution in the muscular strength of the patient. Regarding aerobic fitness, opposite results were found, with a positive evolution in the 2.4 km running test and a negative evolution in the swimming test. In future exercise programs for the improvement of the physical fitness of candidates for the Naval Academy, more emphasis has to be done on specific swimming training.

Keywords: case study, exercise program, Naval Academy, physical fitness

Procedia PDF Downloads 79
1109 Total Organic Carbon, Porosity and Permeability Correlation: A Tool for Carbon Dioxide Storage Potential Evaluation in Irati Formation of the Parana Basin, Brazil

Authors: Richardson M. Abraham-A., Colombo Celso Gaeta Tassinari

Abstract:

The correlation between Total Organic Carbon (TOC) and flow units have been carried out to predict and compare the carbon dioxide (CO2) storage potential of the shale and carbonate rocks in Irati Formation of the Parana Basin. The equations for permeability (K), reservoir quality index (RQI) and flow zone indicator (FZI) are redefined and engaged to evaluate the flow units in both potential reservoir rocks. Shales show higher values of TOC compared to carbonates, as such,  porosity (Ф) is most likely to be higher in shales compared to carbonates. The increase in Ф corresponds to the increase in K (in both rocks). Nonetheless, at lower values of Ф, K is higher in carbonates compared to shales. This shows that at lower values of TOC in carbonates, Ф is low, yet, K is likely to be high compared to shale. In the same vein, at higher values of TOC in shales, Ф is high, yet, K is expected to be low compared to carbonates.  Overall, the flow unit factors (RQI and FZI) are better in the carbonates compared to the shales. Moreso, within the study location,  there are some portions where the thicknesses of the carbonate units are higher compared to the shale units. Most parts of the carbonate strata in the study location are fractured in situ, hence,  this could provide easy access for the storage of CO2. Therefore, based on these points and the disparities between the flow units in the evaluated rock types, the carbonate units are expected to show better potentials for the storage of CO2. The shale units may be considered as potential cap rocks or seals.

Keywords: total organic content, flow units, carbon dioxide storage, geologic structures

Procedia PDF Downloads 150
1108 Bias-Corrected Estimation Methods for Receiver Operating Characteristic Surface

Authors: Khanh To Duc, Monica Chiogna, Gianfranco Adimari

Abstract:

With three diagnostic categories, assessment of the performance of diagnostic tests is achieved by the analysis of the receiver operating characteristic (ROC) surface, which generalizes the ROC curve for binary diagnostic outcomes. The volume under the ROC surface (VUS) is a summary index usually employed for measuring the overall diagnostic accuracy. When the true disease status can be exactly assessed by means of a gold standard (GS) test, unbiased nonparametric estimators of the ROC surface and VUS are easily obtained. In practice, unfortunately, disease status verification via the GS test could be unavailable for all study subjects, due to the expensiveness or invasiveness of the GS test. Thus, often only a subset of patients undergoes disease verification. Statistical evaluations of diagnostic accuracy based only on data from subjects with verified disease status are typically biased. This bias is known as verification bias. Here, we consider the problem of correcting for verification bias when continuous diagnostic tests for three-class disease status are considered. We assume that selection for disease verification does not depend on disease status, given test results and other observed covariates, i.e., we assume that the true disease status, when missing, is missing at random. Under this assumption, we discuss several solutions for ROC surface analysis based on imputation and re-weighting methods. In particular, verification bias-corrected estimators of the ROC surface and of VUS are proposed, namely, full imputation, mean score imputation, inverse probability weighting and semiparametric efficient estimators. Consistency and asymptotic normality of the proposed estimators are established, and their finite sample behavior is investigated by means of Monte Carlo simulation studies. Two illustrations using real datasets are also given.

Keywords: imputation, missing at random, inverse probability weighting, ROC surface analysis

Procedia PDF Downloads 406