Search results for: Joseph K. A. Johnson

Authors: Joseph Abiodun Ayo

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The main purpose of this study was to investigate the science laboratory management practices employed in some colleges of education in Kano State, Nigeria. Four specific objectives were stated to guide the study, four research questions were investigated, four null hypothesis were tested at 0.05 level of significance. A survey design was used and science laboratory management questionnaires which solicit responses that was used in answering the research questions and testing of hypotheses. These questionnaires were distributed to the respective respondents in the sampled colleges. The respondents for the study comprised biology chemistry, physics, integrated science teacher trainers and the paraprofessionals. Data were analyzed using mean and standard deviation to answer the questions. Chi-square statistical technique was used to test the hypothesis. The findings of the study revealed that all procedures on control of laboratory activities were rarely observed. Safety procedures were occasionally practiced. On provision and procurement of laboratory equipment and materials it was observed that both academic and the paraprofessional were not fully involved. While maintenance measures were occasionally observed, furthermore science laboratory management procedures are not frequently practiced. Hence making the acquisition of science process skills by students becoming difficult. To arrest these anomalies, it is recommended that direct labor in the maintenance of laboratory equipment and other apparatus by paraprofessional is crucial. Training of academic and paraprofessional through workshops to acquire technical skills in maintenance of science laboratory equipment be instituted to increase professionalism. Periodic supervision of activities in the science laboratories should be done promptly.

Keywords: laboratory, management, standard, facility

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Authors: Bello Theodora O., Animola Odunayo V., Owoade Johnson T.

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With the advent of Covid-19, online classroom instruction became a very important mode of instruction delivery during which learners were engaged in both collaborative and online interactive learning process, but along with it are challenges as well as its deliverables. This study therefore investigated the various online platform used by the students for learning among fresh undergraduate students of Obafemi Awolowo University, Ile-Ife, Osun Sate. It also assessed the student’s perception towards online learning in the university and examined the influence of collaborative learning among the students. Lastly, it examined the problems that are associated with collaborative online learning instruction in the university. These were with a view to providing empirical information on problems and prospects of online classroom instruction among fresh undergraduate physical science students of Obafemi Awolowo University, Ile-Ife. The study employed a descriptive survey research technique. The population comprised all the fresh undergraduates in physical science departments of Obafemi Awolowo University, Ile-Ife. The sample consisted two hundred freshmen in physical science departments of Obafemi Awolowo University, Ile-Ife, who were selected using simple random techniques. During the selection, a questionnaire was used to collect data from the respondents. The data were analyzed using appropriate descriptive of frequency, simple percentage, and mean. Results showed that Google Meet 149(74.5%), Telegram 120(60.0%), and Google Classroom 143(71.5%), are the prominent online classroom instruction used by the students in Obafemi Awolowo University, Ile-Ife. The results also showed that the freshmen’s perception towards online classroom instruction in Obafemi Awolowo University, Ile-Ife is low with cluster mean of 2.97. It further revealed that collaborative learning enhances the learning ability of below average learners more than that of the above average and average students (73.6%). Finally, the result showed that they are affirmative of the problems associated with online classroom instruction in Obafemi Awolowo University, Ile-Ife with cluster mean of 3.01. The result concluded that most Online platform used by the fresher’s students in Obafemi Awolowo University, Ile-Ife are Google Meet, Telegram and Google Classroom. The students have negatives perception towards online classroom instruction and the students are affirmative of the problems associated with online classroom instruction among physical science freshmen in Obafemi Awolowo University, Ile-Ife.

Keywords: online, instruction, freshmen, physical science, collaborative

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Authors: Thomas F. Ducey, Kristin M. Trippe, James A. Ippolito, Jeffrey M. Novak, Mark G. Johnson, Gilbert C. Sigua

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The Oronogo-Duenweg mining belt –approximately 20 square miles around the Joplin, Missouri area– is a designated United States Environmental Protection Agency Superfund site due to lead-contaminated soil and groundwater by former mining and smelting operations. Over almost a century of mining (from 1848 to the late 1960’s), an estimated ten million tons of cadmium, lead, and zinc containing material have been deposited on approximately 9,000 acres. Sites that have undergone remediation, in which the O, A, and B horizons have been removed along with the lead contamination, the exposed C horizon remains incalcitrant to revegetation efforts. These sites also suffer from poor soil microbial activity, as measured by soil extracellular enzymatic assays, though 16S ribosomal ribonucleic acid (rRNA) indicates that microbial diversity is equal to sites that have avoided mine-related contamination. Soil analysis reveals low soil organic carbon, along with high levels of bio-available zinc, that reflect the poor soil fertility conditions and low microbial activity. Our study looked at the use of several materials to restore and remediate these sites, with the goal of improving soil health. The following materials, and their purposes for incorporation into the study, were as follows: manure-based biochar for the binding of zinc and other heavy metals responsible for phytotoxicity, locally sourced biosolids and compost to incorporate organic carbon into the depleted soils, effective microorganisms harvested from nearby pristine sites to provide a stable community for nutrient cycling in the newly composited 'soil material'. Our results indicate that all four materials used in conjunction result in the greatest benefit to these mine-impacted soils, based on above ground biomass, microbial biomass, and soil enzymatic activities.

Keywords: locally effective microorganisms, biochar, remediation, reclamation

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Authors: Famurewa Olumide Joseph, Akinsulore Adesanmi

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The current study investigated aggressive behaviour and its association with substance use disorder among senior secondary school students in Ilesha, Nigeria. Participants were three hundred and seventy-five (375) comprising (212) females and (163) males of senior secondary school students in Ilesa East and Ilesa West; who were randomly selected among the population of students from the schools. The mean age of the respondents was 14.61 years (S.D = 1.16), with 311 (82.9%) between 14 – 16 years. Female respondents were 212 (56.5%), while male respondents were 163 (43.5%). A cross sectional design was adopted. Three instruments were used for data collection. Buss Perry Aggression Questionnaire, Alcohol Use Disorder Identification Test (AUDIT) and Drug Abuse Screening Test (DAST). It was hypothesized that aggressive behaviour will be associated with substance use disorder among senior secondary school students in Ilesa East and Ilesa West. The result indicated that the overall prevalence of substance use disorder was 16.0%. Chi-Square test exploring the association between aggressive behaviour and substance use disorder shows that there is a significant association between aggressive behaviour and substance use disorder (χ2 =8.55, p =0.014). Results also showed that emotional problem (χ2 (2) =13.0; p = 0.001) was statistically significant while current medications intake (χ2 (2) =2.03; p =0.362) and overall wellbeing (χ2 (4) =2.49; p =0.646) were not statistically significant. There is an inverse association between prosocial behaviour and aggressive behaviour (r= -0.037, p>0.05). This indicates that as the level of prosocial behaviour increases, the level of aggressive behaviour among respondents decreases. However, alcohol use had no correlation with aggressive behaviour (r=0.070, p>0.05). Among the implications stated is that factors such as emotional symptoms, conduct problems, hyperactivity, peer problem and drug use contributed to the prevalence of aggressive behaviour among students. Suggestions for further studies were equally made.

Keywords: aggressive behaviour, alcohol, prevalence, students, substance use disorder (SUD)

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Authors: Joseph George, Anne Kotteswara Roa

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Skin disease is one of the most common and popular kinds of health issues faced by people nowadays. Skin cancer (SC) is one among them, and its detection relies on the skin biopsy outputs and the expertise of the doctors, but it consumes more time and some inaccurate results. At the early stage, skin cancer detection is a challenging task, and it easily spreads to the whole body and leads to an increase in the mortality rate. Skin cancer is curable when it is detected at an early stage. In order to classify correct and accurate skin cancer, the critical task is skin cancer identification and classification, and it is more based on the cancer disease features such as shape, size, color, symmetry and etc. More similar characteristics are present in many skin diseases; hence it makes it a challenging issue to select important features from a skin cancer dataset images. Hence, the skin cancer diagnostic accuracy is improved by requiring an automated skin cancer detection and classification framework; thereby, the human expert’s scarcity is handled. Recently, the deep learning techniques like Convolutional neural network (CNN), Deep belief neural network (DBN), Artificial neural network (ANN), Recurrent neural network (RNN), and Long and short term memory (LSTM) have been widely used for the identification and classification of skin cancers. This survey reviews different DL techniques for skin cancer identification and classification. The performance metrics such as precision, recall, accuracy, sensitivity, specificity, and F-measures are used to evaluate the effectiveness of SC identification using DL techniques. By using these DL techniques, the classification accuracy increases along with the mitigation of computational complexities and time consumption.

Keywords: skin cancer, deep learning, performance measures, accuracy, datasets

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Authors: Benito Garcia-Valero

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This paper analyses the cognitivist value of traditional Japanese theories about aesthetics, art, and literature. These reflections were developed several centuries before actual Cognitive Studies, which started in the seventies of the last century. A comparative methodology is employed to shed light on the similarities between traditional Japanese conceptions about art and current cognitivist principles. The Japanese texts to be compared are Zeami’s treatise on noh art, Okura Toraaki’s Waranbe-gusa on kabuki theatre, and several Buddhist canonical texts about wisdom and knowledge, like the Prajnaparamitahrdaya or Heart Sutra. Japanese contemporary critical sources on these works are also referred, like Nishida Kitaro’s reflections on Zen painting or Ichikawa Hiroshi’s analysis of body/mind dualism in Japanese physical practices. Their ideas are compared with cognitivist authors like George Lakoff, Mark Johnson, Mark Turner and Margaret Freeman. This comparative review reveals the anticipatory ideas of Japanese thinking on body/mind interrelationship, which agrees with cognitivist criticism against dualism, since both elucidate the physical grounds acting upon the formation of concepts and schemes during the production of knowledge. It also highlights the necessity of recovering ancient Japanese treatises on cognition to continue enlightening current research on art and literature. The artistic examples used to illustrate the theory are Sesshu’s Zen paintings and Basho’s classical haiku poetry. Zen painting is an excellent field to demonstrate how monk artists conceived human perception and guessed the active role of beholders during the contemplation of art. On the other hand, some haikus by Matsuo Basho aim at factoring subjectivity out from artistic praxis, which constitutes an ideal of illumination that cannot be achieved using art, due to the embodied nature of perception; a constraint consciously explored by the poet himself. These ideas consolidate the conclusions drawn today by cognitivism about the interrelation between subject and object and the concept of intersubjectivity.

Keywords: cognitivism, dualism, haiku, Zen painting

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Authors: Christiana Ene Ogwuche, Joseph Amupitan, George Ndukwe, Rachael Ayo

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Maesobotrya barteri (Baill), belonging to the family Euphorbiaceae, is a medicinal plant growing widely in tropical Africa. The Aerial plant parts of Maesobotrya barteri (Baill) were collected fresh from Orokam, Ogbadibo local Government of Benue State, Nigeria in July 2013. Taxonomical identification was done by Mallam Musa Abdullahi at the Herbarium unit of Biological Sciences Department, ABU, Zaria, Nigeria. Pulverized aerial parts of Maesobotrya barteri (960g) was exhaustively extracted successively using petroleum ether, chloroform, ethyl acetate and methanol and concentrated in the rotary evaporator at 40°C. The Petroleum ether extract had the second highest activity against test microbes from preliminary crude microbial screenings. The Petroleum ether extract was subjected to phytochemical studies, antimicrobial analysis and column chromatography (CC). The column chromatography yielded fraction PE, which was further purified using preparative thin layer chromatography to give PE1. The structure of the isolated compound was established using 1-D NMR and 2-D NMR spectroscopic analysis and by direct comparison with data reported in literature was confirmed to be a mixture, an isomer of Betulinic acid and Oleanolic acid, both with the molecular weight (C₃₀H₄₈O₃). The bioactivity of this compound was carried out using some clinical pathogens and the activity compared with standard drugs, and this was found to be comparable with the standard drug.

Keywords: Maesobotrya barteri, medicinal plant, bioactivity, petroleum spirit extract, butellinic acid, oleanilic acid

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Authors: Mary A. Bisi-Johnson, Kehinde A. Adediran, Saheed A. Akinola, Hamzat A. Oyelade

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Some of the main problems man contends with are the quantity (source and amount) and quality of water in Nigeria. Scarcity leads to water being obtained from various sources and microbiological contaminations of the water may thus occur between the collection point and the point of usage. Thus, this study aims to assess the general and microbiological quality of domestic water sources and household stored water used within selected areas in Ile-Ife, South-Western part of Nigeria for microbial contaminants. Physicochemical and microbiological examination were carried out on 45 source and stored water samples collected from well and spring in three different local government areas i.e. Ife east, Ife-south, and Ife-north. Physicochemical analysis included pH value, temperature, total dissolved solid, dissolved oxygen, and biochemical oxygen demand. Microbiology involved most probable number analysis, total coliform, heterotrophic plate, faecal coliform, and streptococcus count. The result of the physicochemical analysis of samples showed anomalies compared to acceptable standards with the pH value of 7.20-8.60 for stored and 6.50-7.80 for source samples as the total dissolved solids (TDS of stored 20-70mg/L, source 352-691mg/L), dissolved oxygen (DO of stored 1.60-9.60mg/L, source 1.60-4.80mg/L), biochemical oxygen demand (BOD stored 0.80-3.60mg/L, source 0.60-5.40mg/L). General microbiological quality indicated that both stored and source samples with the exception of a sample were not within acceptable range as indicated by analysis of the MPN/100ml which ranges (stored 290-1100mg/L, source 9-1100mg/L). Apart from high counts, most samples did not meet the World Health Organization standard for drinking water with the presence of some pathogenic bacteria and fungi such as Salmonella and Aspergillus spp. To annul these constraints, standard treatment methods should be adopted to make water free from contaminants. This will help identify common and likely water related infection origin within the communities and thus help guide in terms of interventions required to prevent the general populace from such infections.

Keywords: domestic, microbiology, physicochemical, quality, water

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Authors: Byron Joseph A. Hallar, Annjeannette Alain D. Galang, Maria Visitacion N. Gumabay

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The widespread adoption and increasing proliferation of smartphones that started during the first decade of the twenty-first century have enabled their users to communicate and access information in ways that were merely thought of as possibilities in the few years before the smartphone revolution. A product of the convergence of the cellular phone and portable computer, the smartphone provides an additional important function that used to be the exclusive domain of desktop-bound computers and portable computers: Web Browsing. For increasing numbers of users, the smartphone and allied devices such as tablet computers have become their first and often their only means of accessing the World Wide Web. This has led to the development of websites that cater to the needs of the new breed of smartphone-carrying web users. The smaller size of smartphones as compared with conventional computers has provided unique challenges to web interface designers. The smaller screen size and touchscreen interface have made it much more difficult to read and navigate through web pages that were in most part designed for traditional desktop and portable computers. Although increasing numbers of websites now provide an alternate website formatted for smartphones, problems with ease of use, reliability and usability still remain. This study focuses on the identification of the problems associated with smartphone web interfaces, the compliance with accepted standards of user-oriented web interface design, the strategies that could be utilized to ensure the design of user-centric web interfaces for smartphones, and the identification of the current trends and developments related to user-centric web interface design intended for the consumption of smartphone users.

Keywords: human-computer interaction, user-centered design, web interface, mobile, smartphone

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Authors: Hercules Argyropoulos, Thomas F. Johnson, Nigel B Jackson, Kalliopi Zourna, Daniel G. Bracewell

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Lipid encapsulation has become essential in drug delivery, notably for mRNA vaccines during the COVID-19 pandemic. However, their sterile filtration poses challenges due to the risk of deformation, filter fouling and product loss from adsorption onto the membrane. Choosing the right filtration membrane is crucial to maintain sterility and integrity while minimizing product loss. The objective of this study is to develop a rigorous analytical framework utilizing confocal microscopy and filtration blocking models to elucidate the fouling mechanisms of liposomes as a model system for this class of delivery vehicle during sterile filtration, particularly in response to variations in transmembrane pressure (TMP) during the filtration process. Experiments were conducted using fluorescent Lipoid S100 PC liposomes formulated by micro fluidization and characterized by Multi-Angle Dynamic Light Scattering. Dual-layer PES/PES and PES/PVDF membranes with 0.2 μm pores were used for filtration under constant pressure, cycling from 30 psi to 5 psi and back to 30 psi, with 5, 6, and 5-minute intervals. Cross-sectional membrane samples were prepared by microtome slicing and analyzed with confocal microscopy. Liposome characterization revealed a particle size range of 100-140 nm and an average concentration of 2.93x10¹¹ particles/mL. Goodness-of-fit analysis of flux decline data at varying TMPs identified the intermediate blocking model as most accurate at 30 psi and the cake filtration model at 5 psi. Membrane resistance analysis showed atypical behavior compared to therapeutic proteins, with resistance remaining below 1.38×10¹¹ m⁻¹ at 30 psi, increasing over fourfold at 5 psi, and then decreasing to 1-1.3-fold when pressure was returned to 30 psi. This suggests that increased flow/shear deforms liposomes enabling them to more effectively navigate membrane pores. Confocal microscopy indicated that liposome fouling mainly occurred in the upper parts of the dual-layer membrane.

Keywords: sterile filtration, membrane resistance, microfluidization, confocal microscopy, liposomes, filtration blocking models

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Authors: Amos Olajide Oluyege, Emmanuel Uchechukwu Opara, Sunday Adeniyi Adedutan, Joseph Adeola Fuwape

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This study was conducted to determine the durability of wood-cement particleboards when exposed to attack by subterranean termites, Macrotermes subhylinus. The boards were made from Terminalia superba and Gmelina arborea wood sawdust at nominal board densities (BD) of 1000, 900, and 800 kg/m³ using wood-cement mixing ratios (MR) of 3:1, 2.5:1, 2:1, and 1:1. Above ground durability tests against termite attack were carried out according to ASTM D 2017 for 14 weeks. Results of visual assessment of the wood cement particleboards show that all the board samples had a visual rating that was not less than 7 (i.e., moderate attack) for both species irrespective of the MR and BD. T. superba boards were found to have higher resistance to termite attack compared to their G. arborea counterparts. The mean values for weight loss following exposure ranged from 1.93 to 6.13% and 3.24 to 12.44%. Analysis of variance (ANOVA) results of the weight loss assessment revealed a significant (p < 0.05) effect of species and mixing ratio on the weight loss of the boards due to termite attack with F(₁,₇₂) = 92.890 and P = 0.000 and F(₃,₇₂) = 8.318 and p = 0.000, while board density did not have any significant effect (p > 0.05) with F (₂,₇₂) = 1.307 and p = 0.277. Thus, boards made from a higher mixing ratio had better resistance against termite attacks. Thus, it can be concluded that the durability of cement-bonded particleboards when exposed to subterranean termite attack is not only dependent on the quality of the wood raw material (species) but also on the enhanced protection imparted by the cement matrix; the protection increased with increase in cement/wood mixing ratio.

Keywords: cement-bonded particleboard, mixing ratio, board density, Gmelina arborea, Terminalia superba

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Authors: Danielle A. Walker, Kyle L. Johnson, Tara B. Thomas, Sandor Dorgo, Jacen S. Moore

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Approximately 37 million people worldwide are infected with the Human Immunodeficiency Virus (HIV), with the majority located in sub-Saharan Africa. The relationship existing between HIV incidence and socioeconomic inequity confirms the critical need for programs promoting HIV education, prevention and treatment access. This literature review analyzed 36 sources with a specific focus on the Democratic Republic of Congo, whose critically low socioeconomic status and education rate have resulted in a drastically high HIV rates. Relationships between HIV testing and treatment and barriers to care were explored. Cultural and religious considerations were found to be vital when creating and implementing HIV education and testing programs. Partnerships encouraging active support from community-based spiritual leaders to implement HIV educational programs were also key mechanisms to reach communities and individuals. Gender roles were highlighted as a key component for implementation of effective community trust-building and successful HIV education programs. The efficacy of added support by hospitals and clinics in rural areas to facilitate access to HIV testing and care for people living with HIV/AIDS (PLWHA) was discussed. This review highlighted the need for healthcare providers to provide a network of continued education for PLWHA in clinical settings during disclosure and throughout the course of treatment to increase retention in care and promote medication adherence for viral load suppression. Implementation of culturally sensitive models that rely on community familiarity with HIV educators such as ‘train-the-trainer’ were also proposed as efficacious tools for educating rural communities about HIV. Further research is needed to promote community partnerships for HIV education, understand the cultural context of gender roles as barriers to care, and empower local health care providers to be successful within the HIV Continuum of Care.

Keywords: cultural sensitivity, Democratic Republic of the Congo, education, HIV

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Authors: Njoroge Margaret W., Johnson Deborah

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Gender-specific risk factors for common mental disorders that disproportionately affect women include but are not limited to gender-based violence, socioeconomic disadvantage, sociocultural factors and unrelenting responsibility for the care of others. The overall objective of this study was to assess mental health conditions and their risk factors among women in Garissa County, Kenya. The study adopted both quantitative and qualitative research designs. The study participants were 100 adult women and 20 key informants from different sectors in the region. Data was collected using DSM-5 (PCL-5) and Kessler Psychological Distress, interviews schedule and focus group discussions. Analysis of quantitative data was done using univariate analysis, while qualitative data was analyzed using thematic analysis. The results revealed that about 60% of women presented with moderate to severe psychological distress (PD), while 53% presented with PTSD. Additionally, women who have undergone female genital mutilation had higher PTSD and PD scores. They also presented with low self-esteem, depressive symptoms, sex anxiety, avoidance of reminders and intrusive memories of the event, especially those who developed fistula. The risk factors for poor mental health outcomes include lack of awareness/knowledge of mental health, retrogressive cultural practices (child marriage and female genital mutilation), as well as beliefs about the causes of mental disorders. The study also established that people with mental illness are neglected, abused and stigmatized. Preferred treatment approaches include prayers and the use of witch doctors and traditional healers. The study recommends gendered and culturally responsive interventions geared towards increasing community awareness and knowledge on mental health, reducing stigma and improving mental-health-seeking behaviors for women and girls in the region. Supported by the Ministry of Health, the approach should be spearheaded by trained community lay counselors.

Keywords: women, mental health conditions, cultural beliefs/practices, stigma, poverty, psychological distress, PTSD

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Authors: Joseph Ampratwum, Yaw Nyadu Offei, Afua Ntoaduro, Frank Twum

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The use of computer assistive technology has captured the attention of individuals with visual impairment. Children with visual impairments who are tactual learners have one unique need which is quite different from all other disability groups. They depend on the use of computer assistive technology for reading, writing, receiving information and sending information as well. The objective of the study was to assess students’ competencies in the use of computer assistive technology at Akropong School for the Blind in Ghana. This became necessary because little research has been conducted to document the competencies and challenges in the use of computer among students with visual impairments in Africa. A case study design with a mixed research strategy was adopted for the study. A purposive sampling technique was used to sample 35 students from Akropong School for the Blind in the eastern region of Ghana. The researcher gathered both quantitative and qualitative data to measure students’ competencies in keyboarding skills and Job Access with Speech (JAWS), as well as the other challenges. The findings indicated that comparatively students’ competency in keyboard skills was higher than JAWS application use. Thus students had reached higher stages in the conscious competencies matrix in the former than the latter. It was generally noted that challenges limiting effective use of students’ competencies in computer assistive technology in the School were more personal than external influences. This was because most of the challenges were due to the individual response to the training and familiarity in developing their competencies in using computer assistive technology. Base on this it was recommended that efforts should be made to stock up the laboratory with additional computers. Directly in line with the first recommendation, it was further suggested that more practice time should be created for the students to maximize computer use. Also Licensed JAWS must be acquired by the school to advance students’ competence in using computer assistive technology.

Keywords: computer assistive technology, job access with speech, keyboard, visual impairment

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Authors: Mohamed Ali Ben Halima, Malik Koubi, Joseph Lanfranchi, Yohan Wloczysiak

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This article assesses the consequences on the frequency and duration of ordinary sick leave of the January 2012 and 2018 reforms modifying the scope of sick leave reimbursement in the French civil service. These reforms introduce a one-day waiting period which removes the compensation for the first day of ordinary sick leave. In order to evaluate these reforms, we use an administrative database from the National Pension Fund for local public employees (FPT). The first important result of our data analysis is that the one-day waiting period was not introduced at the same time in the French Local Public Service establishments, or even never in some. This peculiarity allows for an identification strategy using a difference-in-differences method based on the definition at each date of groups of employees treated and not treated by the reform, since establishments that apply the one-day waiting period coexist with establishments that do not apply it. Two types of estimators are used for this evaluation: individual and time fixed effects estimators and DIDM estimators which correct for the biases of the Two Way Fixed Effects one. The results confirm that the change in the sick pay system decreases the probability of having at least one ordinary sick leave as well as the number and duration of these episodes. On the other hand, the estimates show that longer leave episodes are not less affected than shorter ones. Finally, the validity tests of the estimators support the results obtained for the second period of 2018-2019, but suggest estimation biases for the period 2012-2013. The extent to which the endogeneity of the choices of implementation of the reform at the local level impact these estimates needs to be further tested.

Keywords: sick leave, one-day waiting period, territorial civil service, public policy evaluation

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Authors: Ryan S. Johnson, Raeesa Moolla

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Airports are known air pollution hotspots due to the variety of fuel driven activities that take place within the confines of them. As such, people working within airports are particularly vulnerable to exposure of hazardous air pollutants, including hundreds of aromatic hydrocarbons, and more specifically a group of compounds known as BTEX (viz. benzene, toluene, ethyl-benzene and xylenes). These compounds have been identified as being harmful to human and environmental health. Through the use of passive and active sampling methods, the spatial and temporal variability of benzene, toluene, ethyl-benzene and xylene concentrations within the international airport was investigated. Two sampling campaigns were conducted. In order to quantify the temporal variability of concentrations within the airport, an active sampling strategy using the Synspec Spectras Gas Chromatography 955 instrument was used. Furthermore, a passive sampling campaign, using Radiello Passive Samplers was used to quantify the spatial variability of these compounds. In addition, meteorological factors are known to affect the dispersal and dilution of pollution. Thus a Davis Pro-Weather 2 station was utilised in order to measure in situ weather parameters (viz. wind speed, wind direction and temperature). Results indicated that toluene varied on a daily, temporal scale considerably more than other concentrations. Toluene further exhibited a strong correlation with regards to the meteorological parameters, inferring that toluene was affected by these parameters to a greater degree than the other pollutants. The passive sampling campaign revealed BTEXtotal concentrations ranged between 12.95 – 124.04 µg m-3. From the results obtained it is clear that benzene, toluene, ethyl-benzene and xylene concentrations are heterogeneously spatially dispersed within the airport. Due to the slow wind speeds recorded over the passive sampling campaign (1.13 m s-1.), the hotspots were located close to the main concentration sources. The most significant hotspot was located over the main apron of the airport. It is recommended that further, extensive investigations into the seasonality of hazardous air pollutants at the airport is necessary in order for sound conclusions to be made about the temporal and spatial distribution of benzene, toluene, ethyl-benzene and xylene concentrations within the airport.

Keywords: airport, air pollution hotspot, BTEX concentrations, meteorology

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Authors: Ezeugwunne Ifeoma Priscilla, Charles Chinedum Onyenekwe, Joseph Eberendu Ahaneku, Rosemary Adanma Analike, Adesuwa Peace Eidangbe

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This study was designed to assess the effect of malaria parasitaemia on serum reproductive hormone levels of asymptomatic HIV adult subjects. A total of 271 participants aged between 17 and 58 ears were conveniently recruited. 135 asymptomatic HIV-infected subjects participated in the study; 67 of them had malaria parasitaemia. 136 HIV seropositive control subjects, 68 of them had malaria parasitaemia. Blood samples were collected from the participants for the determination of HIV status by immunoassay and immunochromatography. Enzyme-linked immunosorbent assay (ELISA) was used to assay for serum LH, FSH, Estrogen, testosterone, progesterone, prolactin, and PSA levels, CD4+T cell counts by Cyflow method, thick and thin films determination of malaria parasitaemia count and density by WHO. Student's t-tests and ANOVA were used to compare means. P<0.05 was considered statistically significant. The results showed significant differences in serum levels of LH, FSH, PSA, estrogen, progesterone, and testosterone amongst the groups at P<0.05, respectively. The serum levels of LH, FSH, and PSA were significantly higher in malaria-infected asymptomatic HIV subjects than in asymptomatic HIV subjects with malaria parasitaemia (P<0.05 in each case). Also, the serum levels of LH, FSH, PSA, estrogen, and progesterone were significantly higher in malaria-infected asymptomatic HIV subjects compared with malaria-infected HIV seronegative subjects (P<0.05, respectively). The mean MP counts and MP density were significantly higher in asymptomatic HIV subjects compared to HIV seronegative subjects (P<0.05, in each case). The mean serum levels of testosterone were significantly lower in both malaria-infected and malaria uninfected HIV seronegative subjects (P<0.05, in each case). In conclusion, Malaria and HIV co-infection might increase the burden of hypogonadism as well as primary testicular failure, hyperprogesteronaemia, elevated levels of estrogen, and PSA in adult males asymptomatic HIV subjects.

Keywords: malaria parasitaemia, HIV, CD4, reproductive hormones

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Authors: Zuhair Kadhim Jahanger, S. Joseph Antony

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The available studies in the literature which dealt with the scale effects of strip footings on different sand packing systematically still remain scarce. In this research, the variation of ultimate bearing capacity and deformation pattern of soil beneath strip footings of different widths under plane-strain condition on the surface of loose, medium-dense and dense sand have been systematically studied using experimental and noninvasive methods for measuring microscopic deformations. The presented analyses are based on model scale compression test analysed using Particle Image Velocimetry (PIV) technique. Upper bound analysis of the current study shows that the maximum vertical displacement of the sand under the ultimate load increases for an increase in the width of footing, but at a decreasing rate with relative density of sand, whereas the relative vertical displacement in the sand decreases for an increase in the width of the footing. A well agreement is observed between experimental results for different footing widths and relative densities. The experimental analyses have shown that there exists pronounced scale effect for strip surface footing. The bearing capacity factors Nγ rapidly decrease up to footing widths B=0.25 m, 0.35 m, and 0.65 m for loose, medium-dense and dense sand respectively, after that there is no significant decrease in Nγ. The deformation modes of the soil as well as the ultimate bearing capacity values have been affected by the footing widths. The obtained results could be used to improve settlement calculation of the foundation interacting with granular soil.

Keywords: DPIV, granular mechanics, scale effect, upper bound analysis

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Authors: Adegoriola Mayowa I., Lai Joseph H. K., Yung Esther H. K., Chan Edwin H. K.

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Heritage buildings (HBs) as structures with historical and architectural relevance that form an integral part of contemporary society. These buildings deserve to be protected for as long as possible to retain their significance. Therefore, the need to prioritize HB maintenance management is pertinent. However, the decision-making process of HBMM can be relatively daunting. The decision-making challenge may be attributed to the multiple 'stakeholders' expectation and requirement which needs to be met. To this end, professionals in the built environment have identified the need to apply the strategic concept of facilities management (FM) in decision making. Furthermore, the different maintenance dimensions have been applied to maintenance management of residential, commercial, and health facilities. Unfortunately, these different maintenance approaches, such as FM, sustainable FM, urban FM, green FM, and strategic FM, are yet to be fully explored in the decision-making process of HBMM. To bridge this gap, this study focuses on developing a framework for strategic decision-making HBMM, which helps achieve HBMM sustainability. At the study's inception, relevant works of literature in the domains of HBMM and FM were conducted. This review helped in the identification of contemporary maintenance practices and their applicability to HBMM. Afterward, a conceptual framework to aid decision-making in HBMM was developed. This framework integrated the concept of FM scope (people, place, process, and technology) while ensuring that decisions plans were made at strategic, tactical, and operational levels. Also, the different characteristics of HBs and stakeholders' requirements were considered in the framework. The conceptual framework presents a holistic guide for professionals in HBMM to ensure that decision processes and outcomes are practical and efficient. It also contributes to the existing body of knowledge on the integration of FM in HBMM. Furthermore, it will serve as a basis for future studies by applying the conceptualized framework in actual cases.

Keywords: decision-making, facility management, strategy, sustainability, heritage building, maintenance

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Authors: Michael Dare Asemoloye, Segun Gbolagade Jonathan, Rafiq Ahmad, Odunayo Joseph Olawuyi, D. O. Adejoye

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Fungi have potentials for degrading hydrocarbons through the secretion of different enzymes. Crude oil tolerance and degradation by Trichoderma harzianum was investigated in this study with its ability to produce peroxidase enzymes (LiP and MnP). Many fungal strains were isolated from rhizosphere of grasses growing on a crude oil spilled site, and the most frequent strain based on percentage incidence was further characterized using morphological and molecular characteristics. Molecular characterization was done through the amplification of Ribosomal-RNA regions of 18s (1609-1627) and 28s (287-266) using ITS1 and ITS4 combinations and it was identified using NCBI BLAST tool. The selected fungus was also subjected to an in-vitro tolerance test at crude oil concentrations of 5, 10, 15, 20 and 25% while 0% served as control. In addition, lignin peroxidase genes (lig1-6) and manganese peroxidase gene (mnp) were detected and expressed in this strain using RT-PCR technique, its peroxidase producing activities was also studied in aliquots (U/ml). This strain had highest incidence of 80%, it was registered in NCBI as Trichoderma harzianum asemoJ KY488466. The strain KY488466 responded to crude oil concentrations as it increase, the dose inhibition response percentage (DIRP) increased from 41.67 to 95.41 at 5 to 25 % crude oil concentrations. All the peroxidase genes are present in KY488466, and expressed with amplified 900-1000 bp through RT-PCR technique. In this strain, lig2, lig4 and mnp genes were over-expressed, lig 6 was moderately expressed, while none of the genes was under-expressed. The strain also produced 90±0.87 U/ml lignin peroxidase and 120±1.23 U/mil manganese peroxidase enzymes in aliquots. These results imply that KY488466 can tolerate and survive high crude oil concentration and could be exploited for bioremediation of oil-spilled soils, the produced peroxidase enzymes could also be exploited for other biotechnological experiments.

Keywords: crude oil, enzymes, expression, peroxidase genes, tolerance, Trichoderma harzianum

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Authors: Joseph Mary Ssembatya, Blessing Michael Taremwa

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Background: Multiple schwannomas are typically associated with neurofibromatosis type 1 (NF1), but rare cases occur independently of neurofibromatosis. Schwannomas are benign, slow-growing tumors, primarily affecting the cervical and lumbar spine. When large, they may extend over multiple vertebral levels, posing surgical challenges. Case Presentation: A 13-year-old Ugandan Munyankore female patient, presented with a 6-year history of progressive quadriparesis, particularly in the lower limbs. Clinical examination showed hypertonia and hyperreflexia, with no indicators of neurofibromatosis or prior trauma. MRI revealed two “kissing” schwannomas extending from C2 to T2 in the cervical spine. Decompressive surgery was performed through laminoplasty and partial lesion resection, and histology confirmed schwannoma. Two weeks postoperatively, the patient experienced cerebrospinal fluid (CSF) leakage, neck pain, and headache, which required re-operation and duraplasty. Following these interventions, the patient’s neurological status stabilized, with noted improvement in lower limb strength. Discussion: “Kissing” schwannomas are most frequently documented in the cerebellopontine angle, rarely in the spine, and even more rarely in children. While multiple schwannomas are often associated with NF2, this case had no family history or clinical signs of the disorder. Giant invasive spinal schwannomas (GISS) that span multiple vertebrae demand intricate surgical approaches due to their proximity to neurovascular structures. Conclusion: This is the first reported case of kissing cervical schwannomas in a young patient from a low- to middle-income country. Surgical decompression, though challenging, is critical for neurological recovery in such advanced cases.

Keywords: kissing schwannoma, cervical spine, low resource, young, uganda

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Authors: Jerry D. Johnson, Jason A. LaFrance, Matthew A. Ohlson, Shane C. Shope

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The public school system is the largest employer and most impactful factor in the local economy for many rural communities in the United States. The relationship between the school system and the community is symbiotic—they thrive together or decline together. Understanding the perceptions of rural school superintendents (the titular head of the local school district) with regard to rural development is foundational to understanding how the school and community interact and collaborate in key areas like economic development, community development, and workforce development. To investigate those perceptions as they manifest among superintendents in thriving rural communities, a collective case study was designed and conducted to disclose and characterize superintendent perceptions about rural development in three diverse rural settings in the U.S.: Florida, Kansas, and Ohio. Appreciative Inquiry (AI) served as the conceptual framework and supported a focus on identifying and describing assets and strategies/activities that helped explain the positive results in the communities of interest. Implementation of a criterion-based purposive sampling process (using extant data and a nomination process to identify rural superintendents in communities with vibrant economies and recognized the contribution by the schools in rural development) resulted in two superintendents from each of these state settings who participated in semi-structured interviews. Interview transcripts and relevant extant documents were coded and analyzed to produce individual cases with representative themes, after which a cross-case analysis was conducted to generate overarching themes. The overarching themes were then scrutinized and tested through the application of appropriate credibility techniques to promote the trustworthiness of the results. Findings include the importance of building and maintaining relationships that extend beyond the immediate collaboration activity, the importance of collaboration skills, intentionality of practice, and organizational systems/structures as facilitators/affordances. The results offer potential guidance for leveraging the potential for public schools to contribute to their rural development in the communities they serve.

Keywords: collaboration, leadership, rural development, rural schools

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Authors: Kushal Gowda Jayaram, Joseph Huret, Jonathan Quibel, Walter-John Chitty, Gilbert Henaff

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Thermal aging is one of the concerns for the long-term operation of nuclear power plants. Indeed, components in the primary circuit undergo thermal aging while exposed to the chemically active environment of Pressurized Water Reactors (PWRs) over time. Among the materials used in the reactor components, Alloy 690 can be found in some critical components for nuclear safety. Despite its importance, research on the effect of thermal aging on the microstructural changes and low cycle fatigue (LCF) behavior of Alloy 690 remains limited. This study aims to assess the impact of thermal aging on the fatigue life of Alloy 690. The as-received sample underwent aging at 420°C for 4000 hours, representing the equivalent aging of 60 years in reactor working conditions. First, the characterization of the area and density of intergranular and intragranular precipitates was performed to understand the microstructural changes in the aged specimen. Then, low cycle fatigue tests were conducted on the as received and aged samples at varying strain amplitudes. To investigate the influence of thermal aging on the fatigue behavior of Alloy 690, fracture surfaces were analyzed to estimate fatigue crack growth rates based on striation spacing measurements. Additionally, the axially cut fractured samples have undergone analysis using Electron Backscatter Diffraction (EBSD) to understand the effect of aging on strain localization near the crack path. Results indicate that while the characterization of the area and density of intergranular precipitates in the aged specimen (for 2000 hours, approximately 30 years) showed no significant changes, there was a slight increase in the area and density of intragranular precipitates under the same conditions.

Keywords: alloy 690, thermal aging, low cycle fatigue, precipitates

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Authors: Viveka Jackson, Erouscilla Joseph, Denise Beckles, Thomas Christopher

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Sulphur Dioxide (SO2) has been defined as a non-flammable, non-explosive, colourless gas, having a pungent, irritating odour, and is one of the main gases emitted from volcanoes. Sulphur dioxide has been recorded in concentrations hazardous to humans (0.25 – 0.5 ppm (~650 – 1300 μg/m3), downwind of many volcanoes and hence warrants constant air-quality monitoring around these sites. It has been linked to an increase in chronic respiratory disease attributed to long-term exposures and alteration in lung and other physiological functions attributed to short-term exposures. Sulphur Springs in Saint Lucia is a highly active geothermal area, located within the Soufrière Volcanic Centre, and is a park widely visited by tourists and locals. It is also a current source of continuous volcanic emissions via its many fumaroles and bubbling pools, warranting concern by residents and visitors to the park regarding the effects of exposure to these gases. In this study, we introduce a novel SO2 measurement system for the monitoring and quantification of ambient levels of airborne volcanic SO2 using low-cost technology. This work involves the extensive production of low-cost SO2 monitors/samplers, as well as field examination in tandem with standard commercial samplers (SO2 diffusion tubes). It also incorporates community involvement in the volcanic monitoring process as non-professional users of the instrument. We intend to present the preliminary monitoring results obtained from the low-cost samplers, to identify the areas in the Park exposed to high concentrations of ambient SO2, and to assess the feasibility of the instrument for non-professional use and application in volcanic settings

Keywords: ambient SO2, community-based monitoring, risk-reduction, sulphur springs, low-cost

Procedia PDF Downloads 468

Authors: Pilly Joseph Kagosi

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The study aims at assessing challenges observed during implementation of participatory irrigation management (PIM) approach for food security in semi-arid areas of Tanzania. Data were collected through questionnaire, PRA tools, key informants discussion, Focus Group Discussion (FGD), participant observation and literature review. Data collected from questionnaire was analyzed using SPSS while PRA data was analyzed with the help of local communities during PRA exercise. Data from other methods were analyzed using content analysis. The study revealed that PIM approach has contribution in improved food security at household level due to involvement of communities in water management activities and decision making which enhanced availability of water for irrigation and increased crop production. However there were challenges observed during implementation of the approach including; minimum participation of beneficiaries in decision making during planning and designing stages, meaning inadequate devolution of power among scheme owners; Inadequate and lack of transparency on income expenditure in Water Utilization Associations’ (WUAs), water conflict among WUAs members, conflict between farmers and livestock keepers and conflict between WUAs leaders and village government regarding training opportunities and status; WUAs rules and regulation are not legally recognized by the National court and few farmers involved in planting trees around water sources. However it was realized that some of the mentioned challenges were rectified by farmers themselves facilitated by government officials. The study recommends that, the identified challenges need to be rectified for farmers to realize impotence of PIM approach as it was realized by other Asian countries.

Keywords: potentials of implementing participatory approach, challenges of participatory approach, irrigation management, Tanzania

Procedia PDF Downloads 307

Authors: Fhulufhelo Ramukhithi, Kgothatso Masethe, Tlou Chokoe, Ayanda Maqhashu, Julius Sebei, Tshililo Raphulu, Joseph Mugwabana

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Phenotypic characterisation ensures that the physical appearance of an animal is well documented. The information provided by this phenotypic characterisation study is important for planning management and the use of animal genetic resources. The aim of this study was to characterise the phenotypic characteristics of Bapedi sheep. Bapedi sheep are at risk of extinction like most of the indigenous breeds. As a result, a total of 196 Bapedi ewes and 35 rams were used. Phenotypic-qualitative characteristics were evaluated through visual appraisal. Phenotypic-quantitative characteristics such as body parts measurements were obtained using a flexible tape (cm), while body weight were obtained by using a weighing scale (kg). Bapedi rams (97 %) had higher satisfactory body condition when compared to ewes (75 %). A higher proportion of Bapedi sheep that did not have ticks observed (ewes = 87 % and rams = 91 %). Brown and white colour combination (head x body) was dominating in Bapedi sheep (80 % ewes and 91 % rams). Bapedi ewes did not have any horns; however, 3 % of rams had them. Bapedi sheep had a higher proportion of brown eyes, moderate neck, stiff sideways ears and normal front legs. Bapedi rams had a higher proportion of well-balanced and good attached testicles. Bapedi ewes had average (45 %), small (40 %) and big udders (15 %). Bapedi rams had a significantly higher body weight, height, depth, hearth girth circumference, rump width, hind leg width and length compared to ewes. However, both Bapedi rams and ewes had similar age, body condition score, tail length, length below hock and knee. In conclusion, Bapedi sheep had a higher satisfactory body condition and brown and white colour combination. Some of Bapedi rams’ quantitative characteristics were higher compared to ewes.

Keywords: extinction, indigenous, phenotypic, smallstock

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Authors: Iman Shabanzadeh

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The economic growth and the special model of development in China have caused sensitivity in the public opinion of the world regarding the nature of this growth and development. In this regard, the Chinese have tried to put an end to such alarming procedures by using all the tools at their disposal and seek to present a peaceful and cooperative image of themselves. In this way, one of the most important diplomatic tools that Beijing has used to reduce the concerns caused by the Threat Theory has been the use of soft power resources and its tools in its development policies. This article begins by analyzing the concept of soft power and examining its foundations in international relations, and continues to examine the components of soft power in its Chinese version. The main purpose of the article is to figure out about the position of West Asia in China's soft power strategy and resources China use to achieve its goals in this region. In response to the main question, the paper's hypothesis is that soft power in its Chinese version had significant differences from Joseph Nye's original idea. In fact, the Chinese have imported the American version of soft power and adjusted, strengthened and, in other words, internalized it with their abilities, capacities and political philosophy. Based on this, China's software presence in West Asia can be traced in three areas. The first source of China's soft power in this region of West Asia is cultural in nature and is realized through strategies such as "use of educational tools and methods", "media methods" and "tourism industry". The second source is related to political soft power, which is applied through the policy of "balance of influence" and the policy of "mediation" and relying on the "ideological foundations of Confucianism". The third source also refers to China's economic soft power and is realized through three tools: "energy exchanges", "foreign investments" and "Belt-Road initiative". The research method of this article is descriptive-analytical.

Keywords: soft power, cooperative power, china, west asia

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Authors: Cornelius Arome Omatola, Ropo Ebenezer Ogunsakin, Anyebe Bernard Onoja, Martin-Luther Oseni Okolo, Joseph Abraham-Oyiguh, Kehinde Charles Mofolorunso, Phoebe Queen Akoh, Omebije Patience Adejo, Joshua Idakwo, Therisa Ojomideju Okeme, Danjuma Muhammed, David Moses Adaji, Sunday Ocholi Samson, Ruth Aminu, Monday Eneojo Akor

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Gastroenteritis viruses are the leading etiologic agents of diarrhea in children worldwide. We present data from thirty-three (33) eligible studies published between 2003 and 2023 from African countries bearing the brunt of the virus-associated diarrheal mortality. Random effects meta-analysis with proportion, subgroups, and meta-regression analyses were employed. Overall, rotavirus with estimated pooled prevalence of 31.0% (95% CI 24.0–39.0) predominated in all primary care visits and hospitalizations, followed by norovirus, adenovirus, sapovirus, astrovirus, and aichivirus with pooled prevalence estimated at 15.0% (95% CI 12.0–20.0), 10% (95% CI 6-15), 4.0% (95% CI 2.0–6.0), 4% (95% CI 3-6), and 2.3% (95% CI 1-3), respectively. Predominant rotavirus genotype was G1P[8] (38%), followed by G3P[8] (11.7%), G9P[8] (8.7%), and G2P[4] (7.1%); although, unusual genotypes were also observed, including G3P[6] (2.7%), G8P[6] (1.7%), G1P[6] (1.5%), G10P[8] (0.9%), G8P[4] (0.5%), and G4P[8] (0.4%). The genogroup II norovirus predominated over the genogroup I-associated infections (84.6%, 613/725 vs 14.9%, 108/725), with the GII.4 (79.3%) being the most prevalent circulating genotype. In conclusion, this review showed that rotavirus remains the leading driver of viral diarrhea requiring health care visits and hospitalization among under-five years children in Africa. Thus, improved rotavirus vaccination in the region and surveillance to determine the residual burden of rotavirus and the evolving trend of other enteric viruses are needed for effective control and management of cases.

Keywords: enteric viruses, rotavirus, norovirus, adenovirus, astrovirus, gastroenteritis

Procedia PDF Downloads 98

Authors: Saarah Juman, Ilona Johnson, Stephen Richmond, Brett Duane, Sheelagh Rogers

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Introduction: Researchers suggest that within 50 years or less, the available supply of a range of metals will be exhausted, potentially leading to increases in resource conflict and largescale production shortages. The healthcare, dental and orthodontic sectors will undoubtedly be affected as stainless steel instruments are generally heavily relied on. Although changing orthodontic archwires are unavoidable and necessary to allow orthodontic tooth movement through the progression of an archwire sequence with fixed appliances, they are thought to be manufactured in excess of what is needed. Furthermore, orthodontic archwires require trimming extraorally to allow safe intraoral insertion, thus contributing to unnecessary waste of natural resources. Currently, there is no evidence to support the optimisation of archwire length according to orthodontic fixed appliance stage. As such, this study aims to quantify archwire excess (extraoral archwire trimmings) for different stages of orthodontic fixed appliance treatment. Methodology: This prospective, observational, quantitative study observed trimmings made extraorally against pre-treatment study models by clinicians over a 3-month period. Archwires were categorised into one of three categories (initial aligning, sequence, working/finishing arcwhires) within the orthodontic fixed appliance archwire sequence. Data collection included archwire material composition and the corresponding length and weight of excess archwire. Data was entered using a Microsoft Excel spreadsheet and imported into statistical software to obtain simple descriptive statistics. Results: Measurements were obtained for a total of 144 archwires. Archwire materials included nickel titanium and stainless steel. All archwires observed required extraorally trimming to allow safe intraoral insertion. The manufactured lengths of orthodontic initial aligning, sequence, and working/finishing arcwhires were at least 31%, 26%, and 39% in excess, respectively. Conclusions: Orthodontic archwires are manufactured to be excessively long at all orthodontic archwire sequence stages. To conserve natural resources, this study’s findings support the optimisation of orthodontic archwire lengths by manufacturers according to the typical stages of an orthodontic archwire sequence.

Keywords: archwire, orthodontics, sustainability, waste

Procedia PDF Downloads 197

Authors: Oluwatoyin Joseph Gbadeyan, Sarp Adali, Bright Glen, Bruce Sithole

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Sodium lauryl surfactant concentration optimization, for nanoparticle production, provided the platform for advanced research studies. Different concentrations (0.05 %, 0.1 %, and 0.2 %) of sodium lauryl surfactant was added to snail shells powder during milling processes for producing CaCO3 at smaller particle size. Epoxy nanocomposites prepared at filler content 2 wt.% synthesized with different volumes of sodium lauryl surfactant were fabricated using a conventional resin casting method. Mechanical properties such as tensile strength, stiffness, and hardness of prepared nanocomposites was investigated to determine the effect of sodium lauryl surfactant concentration on nanocomposite properties. It was observed that the loading of the synthesized nano-calcium carbonate improved the mechanical properties of neat epoxy at lower concentrations of sodium lauryl surfactant 0.05 %. Meaningfully, loading of achatina fulica snail shell nanoparticles manufactures, with small concentrations of sodium lauryl surfactant 0.05 %, increased the neat epoxy tensile strength by 26%, stiffness by 55%, and hardness by 38%. Homogeneous dispersion facilitated, by the addition of sodium lauryl surfactant during milling processes, improved mechanical properties. Research evidence suggests that nano-CaCO3, synthesized from achatina fulica snail shell, possesses suitable reinforcement properties that can be used for nanocomposite fabrication. The evidence showed that adding small concentrations of sodium lauryl surfactant 0.05 %, improved dispersion of nanoparticles in polymetrix material that provided mechanical properties improvement.

Keywords: sodium lauryl surfactant, mechanical properties , achatina fulica snail shel, calcium carbonate nanopowder

Procedia PDF Downloads 147