57 research outputs found
Photocatalytic and biological oxidation treatment of real textile wastewater
Abstract
In this study, the discoloration of wastewater containing azo dyes by chemical oxidation process combined with a biological treatment was evaluated and applied to real textile wastewater generated from one Ethiopian industrial site. The use of TiO2 as photocatalyst and the effect of the addition of H2O2 on color removal was first investigated. Photocatalysis was followed by aerobic biological treatment, and their combination resulted in a high extent of color removal (93.3%) and chemical oxygen demand (COD) reduction (90.4%). This was reached without pH correction and with low energy consumption compared to the implementation of AOPs alone. This study performed with real textile wastewater allows the direct extrapolation of the data for the design of a cost-effective and applicable treatment procedure at a pilot scale.
Graphic abstrac
Top Level Metaphors That Shape the Discussion of the Anthropocene and Their Use for Secondary School Science Classrooms
‘Conflict between anti-money laundering and anti-terrorism finance laws requirements and bank secrecy and confidentiality laws’
Search-Based Test Generation Targeting Non-Functional Quality Attributes of Android Apps
Mobile apps form a major proportion of the software marketplace and it is crucial to ensure that they meet both functional and nonfunctional quality thresholds. Automated test input generation can reduce the cost of the testing process. However, existing Android test generation approaches are focused on code coverage and cannot be customized to a tester\u27s diverse goals---in particular, quality attributes such as resource use.We propose a flexible multi-objective search-based test generation framework for interface testing of Android apps---STGFA-SMOG. This framework allows testers to target a variety of fitness functions, corresponding to different software quality attributes, code coverage, and other test case properties. We find that STGFA-SMOG outperforms random test generation in exposing potential quality issues and triggering crashes. Our study also offers insights on how different combinations of fitness functions can affect test generation for Android apps
A survey on occurrence of internal and external fish parasites and causes of fish population reduction in Lake Hashenge, Tigray, Ethiopia
A cross-sectional study was conducted from November 2015 to June 2016 to determine the occurrence of internal and external parasites in wild fish population of Lake Hashenge and identify the causes of the trends in reduction of fish population. A total of 125 randomly selected fish samples comprising 122 (97.6%) Nile tilapia (Oreochromis niloticus) and 3(2.4%) T. zilli were examined for internal helminthes and external parasites. Overall, 37.6% (47/125) of fish were infested by internal parasites (adults or eggs/larva) while none of them were infested with external parasites. The internal parasites recovered were Clinostomum, Acanthocephalues and Capillaria accounting for 15.2%, 11.2%, and 7.2% of the total infection respectively, while 4% had mixed infection. Moreover, the distribution of parasitic genera were found to be significantly different (p<0.05) with respect to sex, weight, and lengths of the sampled fish, in that females (n=48, 24.8%), fish with body weight 500-1000g (n=89, 30.4%), and length 20-40cm (n=68, 22.4%) were found to be more infected. Most of the respondents (92%) indicated a great reduction in the water and the fish population of the lack from its previous state. All of the respondents have stated that residents of the area wash their clothes in the Lake using synthetic and/or natural detergents and 86% of the respondents believed that Lake Hashenge receives flooding water from nearby uphills and the people use the water from the Lake for small scale irrigation purposes. These findings demand a future focus and stretch of intervention programs for alleviation of the problems facing the Lake before its exhaustion.Keywords: Fish; Lake Hashenge; Parasites; Prevalence; Population reductio
Application of an Integrated Assessment Scheme for Sustainable Waste Management of Electrical and Electronic Equipment: The Case of Ghana
The effective management of solid waste, including waste electrical and electronic equipment (WEEE) in developing countries poses significant challenges. This paper reports on the development and utilization of a multi-criteria tool to improve the management of WEEE in Agbogbloshie, in Ghana. The tool was able to successfully evaluate key economic, social and environmental factors faced by workers and to suggest areas for improvement. In particular, the evaluation and comparison of different scenarios suggested that the best solution is the evolution from informal to formal management of WEEE, with workers provided with personal protective equipment, and the introduction of refurbishment activities, with the sale of components in the second-hand market. While it would require further use in other contexts, the tool could be adapted and employed for a range of other waste streams and in other developing countries
Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021
BackgroundDisorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021.MethodsWe estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined.FindingsGlobally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer.InterpretationAs the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed
Exploring inquiry based science education at secondary school level
This study investigated the nature and extent of inquiry practices in high school science classrooms in a South African city. The study comprised of two phases, namely a small survey followed by a multi-case study. Data were collected using a questionnaire during the survey followed by interviews and classroom lesson observations during the multi-case study. The respondents were Grade 10 science teachers in well performing city schools.
During the survey, I distributed a questionnaire to thirty schools in the city. Only ten teachers returned completed questionnaires. Four of these teachers agreed to participate in the multi-case study.
Although the survey indicated that most of the teachers have a good understanding of the meaning of inquiry, and that they believe that inquiry is an effective teaching strategy, the actual practicing of inquiry based teaching was confirmed in only two classrooms during the study. In both cases, guided inquiry laboratory activities were observed. It was also found that some respondents misunderstood the meaning of inquiry teaching, regarding it as simply asking questions.
The findings from this study cannot be generalised to a larger population, however, they give a deeper insight into the situation in well performing city schools in the country.Dissertation (MEd)--University of Pretoria, 2015.tm2015Science, Mathematics and Technology EducationMEdUnrestricte
Knowledge Sharing Practice and its Associated Factors of Healthcare Professionals of Public Hospitals, Mekelle, Northern Ethiopia
Knowledge Sharing Practice and its Associated Factors of Healthcare Professionals of Public Hospitals, Mekelle, Northern Ethiopi
- …