40 research outputs found
Geological and hydrogeological features controlling mechanisms of fluoride enrichment in groundwater in the East African Rift System
No full textEast African Rift Valley, fluoride , rift architecture, groundwate
Corruption - no rule of law - no democracy: could separately elected Attorneys General in a divided executive give Africa new hope? Experiences from the U. States of A
No full textThesis (LLM (Human Rights and Democratisation in Africa)) -- University of Pretoria, 2008.A Dissertation submitted to the Faculty of Law University of Pretoria, in partial fulfilment of the requirements for the degree Masters of Law (LLM in Human Rights and Democratisation in Africa). Prepared under the supervision of Mr. Tilahun Teshome
in association with the Addis Ababa UniversityHistory has proven that, if freed from the grasp of the unitary executive, the
elected Attorney General flourishes as a lawyer for the law dedicated above all else to the "public interest." In light of these proven benefits, the pressing question becomes whether this tested design can help the people of Africa as they fight to reclaim their wayward governments. Might a popularly elected Attorney General steady the bridge so Africa can pass through to freedom and prosperity? More immediately,
does the divided executive with its elected attorney general represent a new hope for
Africa in combating corruption? The author takes a critical look at the evolution of the elected Attorney General and uses the role of the Attorney General in the United States of America as an example.
The author concludes that perhaps now is the time to start creating the history of Africa’s ultimate escape from the endless vestiges of colonialism still embedded in the unitary executive. Maybe now is the time for the peoples of Africa to borrow an idea from their American cousins and get their own lawyer!http://www.chr.up.ac.za/Centre for Human RightsLL
A Survey on Goal-Oriented Semantic Communication: Techniques, Challenges, and Future Directions
No full textAbstract
Although many proposals have been developed for the sixth-generation (6G) technology, realizing 6G is fraught with numerous fundamental interdisciplinary, multidisciplinary, and transdisciplinary challenges. To mitigate some of these challenges, goal-oriented semantic communication (SemCom) has emerged as a promising 6G technology enabler. This enabler employs only semantically-relevant information for successful task execution while minimizing power usage, bandwidth consumption, and transmission delay. On the other hand, 6G is essential for realizing major goal-oriented SemCom use cases such as autonomous transportation. These paradigms of 6G for goal-oriented SemCom and goal-oriented SemCom for 6G call for a tighter integration of 6G and goal-oriented SemCom. To facilitate this purpose, this survey paper exposes the fundamental challenges of 6G; details the notion of goal-oriented SemCom and its state-of-the-art research landscape; presents state-of-the-art trends, use cases, and frameworks of goal-oriented SemCom; exposes the fundamental and major challenges of goal-oriented SemCom; and offers promising future research directions for goal-oriented SemCom. Consequently, this survey article stimulates numerous lines of research on goal-oriented SemCom theories, algorithms, and realization.Abstract
Although many proposals have been developed for the sixth-generation (6G) technology, realizing 6G is fraught with numerous fundamental interdisciplinary, multidisciplinary, and transdisciplinary challenges. To mitigate some of these challenges, goal-oriented semantic communication (SemCom) has emerged as a promising 6G technology enabler. This enabler employs only semantically-relevant information for successful task execution while minimizing power usage, bandwidth consumption, and transmission delay. On the other hand, 6G is essential for realizing major goal-oriented SemCom use cases such as autonomous transportation. These paradigms of 6G for goal-oriented SemCom and goal-oriented SemCom for 6G call for a tighter integration of 6G and goal-oriented SemCom. To facilitate this purpose, this survey paper exposes the fundamental challenges of 6G; details the notion of goal-oriented SemCom and its state-of-the-art research landscape; presents state-of-the-art trends, use cases, and frameworks of goal-oriented SemCom; exposes the fundamental and major challenges of goal-oriented SemCom; and offers promising future research directions for goal-oriented SemCom. Consequently, this survey article stimulates numerous lines of research on goal-oriented SemCom theories, algorithms, and realization
Corrigendum to “Origin of shuttle-free sulfurized polyacrylonitrile in lithium-sulfur batteries” [J. Power Sources 492 (30 April 2021) 229508]
No full textThe authors regret to find a missing author in the authorship of this work. Tilahun Awoke Zegeye was not included as an author in the published article. Dr. Tilahun Awoke Zegeye was responsible for some Raman measurements and data curation. Unfortunately, during the long revision and collaborative process, his name was accidentally deleted. The corrected Authorship and Author Contributions Statement appears below. The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. All the co-authors agree to this change. The corrected Authorship is as follows: “Chen-Jui Huanga,1, Ju-Hsiang Chenga,1, Wei-Nien Sub, Pouya Partovi-Azarc, Liang- Yin Kuod, Meng-Che Tsaib, Tilahun Awoke Zegeyea, Ming-Hsien Line, Sara Panahian Jandf, Ting-Shan Chang, Nae-Lih Wuh, Payam Kaghazchid, Hongjie Daii, Peter Maria Biekerj, Bing-Joe Hwanga,b,g,*” The corrected Authorship Contribution Statement is as follows: Chen-Jui Huang: fabricated the samples and carried out the experiments, characterizations, data analysis, and, Writing - original draft. Ju-Hsiang Cheng: fabricated the samples and carried out the experiments, characterizations, data analysis, and, Writing - original draft. Wei-Nien Su: reviewed the results and helped the, Writing - original draft. Pouya Partovi-Azar: conducted the theoretical analysis. Liang-Yin Kuo: conducted the theoretical analysis. Meng-Che Tsai: conducted the theoretical analysis. Tilahun Awoke Zegeye: Data Curation of Raman results. Ming-Hsien Lin: helped carry out the SEM and ex-situ Raman measurements. Sara Panahian Jand: conducted the theoretical analysis. Ting- Shan Chan: helped carry out the XAS measurement. Nae-Lih Wu: helped review the results. Payam Kaghazchi: managed the project and reviewed the results, data analysis, and, Writing - original draft. Hongjie Dai: helped review the results. Peter Maria Bieker: helped review the results. Bing-Joe Hwang: managed the project and reviewed the results, data analysis, and, Writing - original draft. All authors read and commented on the manuscript.link_to_subscribed_fulltex
Characterisation of the electrochemical properties of maize grain contaminated with aflatoxin.
No full textMasters Degree. University of KwaZulu-Natal, Pietermaritzburg.Abstract available in pdf.Author is captured as Onyando, Francis Collins Muga on the university system, however the author uses Muga, Francis Collins in all his academic publications
Model Uncertainty of Non-Linear Finite Element Analysis of Reinforced Concrete Beams without Shear Reinforcement: Examining the Effect of Modelling Strategies and Modes of Failure
No full textThe aim of this thesis project is to investigate the model uncertainty of non-linear finite element analysis of reinforced concrete structures at ultimate limit state by focusing on concrete cracking model, concrete-reinforcement interaction model and mesh size. Following this, eight finite element modelling strategies are developed and 67 benchmark experiments on reinforced concrete beams without shear reinforcement are analysed.The measure of model uncertainty is using the ratio of experimental to numerical failure load and comparing predicted and experimental failure behaviour. A ratio that deviates form 1 indicates high model uncertainty with values <1 representing non-conservative predictions and values >1 representing conservative predictions.The eight modelling strategies are categorized into three groups. The first group is used to select shear retention model for the fixed crack concept and to study the behaviour of fixed and rotating crack concepts in combination with embedded reinforcement. The damage based and aggregate-size based shear retention models are investigated resulting in a mean model uncertainty ratio of 0.86 and 0.82 respectively. This indicates that on average both predict higher ultimate capacity when compared to experimental results with the aggregate size based shear retention model exhibiting higher model uncertainty. The aggregate size based model is not capable of predicting shear and mixed failure types while the damage based predicted accurate failure modes. On the other hand, the rotating crack model with embedded reinforcement shows failure due to delamination of the concrete cover. Replacement of the perfectly bonded embedded reinforcement by reinforcement with bond-slip demonstrated to predict accurate failure modes.The second group has the fixed crack model with damage based shear retention model and embedded reinforcement, which is referred to as F-EB-2-D and rotating crack model with bond-slip reinforcement named R-BS-2. Both modelling strategies have 50mm mesh size and result in mean model uncertainty ratio of 1.11 and 1.06 respectively which implies that on average both give conservative predictions of the ultimate capacity with R-BS-2 showing a better prediction. Both modelling strategies give higher model uncertainty for experiments with shear failure with F-EB-2-D and R-BS-2 predicting accurate failure modes for 48% and 51% of the experiments respectively. The beams with reinforcement ratio of ≤ 0.6% showed on average less model uncertainty in F-EB-2-D and R-BS-2. The third group is made by refining the mesh size of F-EB-2-D and R-BS-2 from 50mm to 25mm in critical section of the beams to formulate the modelling strategies F-EB-3-D and R-BS-3 . 16 experiments are re-analysed using this group and a lowered mean model uncertainty ratio of 0.93 and 0.95 is obtained for F-EB-3-D and R-BS-3 respectively although this is slightly non-conservative with accurate predictions for 81% of the 16 experiments. The correlation between model uncertainty and numerical failure mechanism is made using a ductility index which is defined as the ratio of the plastic dissipated energy in the reinforcement and the system. However the ductility index should be used together with model uncertainty if it is verified that the correct equations are solved accurately in the finite element analysis.Civil Engineerin
Chronically retained gauze (gossypiboma) resembling a mature cystic teratoma after Cesarean delivery: a case report
No full textAbstract Background A foreign body left behind during an operation is a medico-legal issue. It is an infrequent but avoidable surgical complication, which must be kept in mind in any postoperative patient who presents with pain, infection, or palpable mass. Case summary The author presents a rare case of chronic gossypiboma following a Cesarean delivery in a 40-year-old woman, who was a Para III patient from Western Ethiopia. She had been experiencing dull, aching pain since her previous Cesarean section four years prior. To address her complaints, she visited multiple health facilities where she was prescribed pain relief medications and antibiotics. The patient was eventually taken to the operating room with a preliminary diagnosis of a mature cystic teratoma. However, during laparotomy, surgical gauze was discovered and successfully removed. Conclusion In patients who have previously undergone surgery for obstetric or other gynecological procedures and present with vague abdominal complaints, it is important to consider the possibility of a chronic gossypiboma mimicking a mass of unknown origin. Following established surgical protocols and implementing new preventive measures, such as using tagged gauze/ radio-opaque markers, and ongoing staff training could help reduce or prevent the occurrence gossypiboma. Additionally, the author advises performing delicate surgical procedures to remove retained gauze to prevent bleeding and tissue damage. The gauze should be gently lifted, and the wound must be examined for any damage
The economic implication of animal feed scarcity on farm intensifcation, food production and consumption : empirical evidence from Tigrai, Ethiopia
No full textThis dissertation analyses cattle farming in order to (i) test the hypotheses of Boserup and Malthus in the merits of distinguishing both direct and indirect effects of population pressure on farm intensification, and (ii) test the downward spiral hypothesis which states that people in poverty are forced to deplete resources to survive, and this environmental depletion further impoverishes them. The main dissertation is composed of 4 manuscripts. The first paper attempts to examine the effect of rising population pressure on (i) farm and herd size (ii) modern input use and (iii) farm output by applying a recursive estimation combined with a control function approach using data from 518 randomly selected farmers. The finding reveals that both Malthusian and Boserupian forces co-exist. Population pressure affected both input demand and output supply. Consistent with Malthus theory, high population pressure is found to be associated with small farm size and herd size. As predicted by Boserup’s theory, the use of modern input and output supply initially increase with increasing population pressure but decline again when population densities pass a critical threshold (800 persons/km²), supporting Malthus’ hypothesis.
In the second Paper, we pay specific attention to the economic effect of resource (grazing, water and crop residue) scarcity measured in a traveling time and shadow cost on labor for crop farming and crop food production. The analysis in this paper was conducted in order to test the hypothesis that increasing time spent on searching for grazing, water and collecting straw has a negative effect on crop farm labor time and crop farm production based on non-separable household model. Our results favor the hypothesis of a negative relationship between labor input to crop farming and resource scarcity. In aggregate, the findings confirm that reducing time spent looking for water and animal feed increases food production. Likewise, our results show that moderate significant difference in crop output value between male and female resulting from a resource scarcity. The quantile regression also proved that the effects of these scarce resources are heterogeneous.
Paper 3 focus on the link between animal resource scarcities measured in a traveling time and shadow cost and welfare and food security drawing on a separable farm household model. The theoretical prediction that resource scarcity adversely affects household per capita food consumption expenditure (welfare) and food security, as predicted by the downward spiral hypothesis was tested using a double log IV 2SLS for the case of welfare and probit model in the case of food security. In aggregate, our principal findings confirmed that resource scarcity affect household welfare and food security adversely and effect is not uniform across the food income groups.
Paper 4 assess the effects of production risk and time preference on animal feeding practice use and feeding choice. Using the theoretical framework suggested by Antle (1987) and Koundouri et al. (2006), the author shows production risk to be the main determinants of stall feeding adoption and its full application using estimated moments of the value of milk production. It further considers discount factor and animal shock exposure into account as key factors of SF adoption and its application. Our empirical analysis revealed that production risk and time preferences are key determinant of SF adoption and full year application
Konsekvenser av fórknapphet på kvegdrift, matproduksjon og forbru : empirisk evidens fra Tigrai, Etiopia
No full textThis dissertation analyses cattle farming in order to (i) test the hypotheses of Boserup and Malthus in the merits of distinguishing both direct and indirect effects of population pressure on farm intensification, and (ii) test the downward spiral hypothesis which states that people in poverty are forced to deplete resources to survive, and this environmental depletion further impoverishes them. The main dissertation is composed of 4 manuscripts. The first paper attempts to examine the effect of rising population pressure on (i) farm and herd size (ii) modern input use and (iii) farm output by applying a recursive estimation combined with a control function approach using data from 518 randomly selected farmers. The finding reveals that both Malthusian and Boserupian forces co-exist. Population pressure affected both input demand and output supply. Consistent with Malthus theory, high population pressure is found to be associated with small farm size and herd size. As predicted by Boserup’s theory, the use of modern input and output supply initially increase with increasing population pressure but decline again when population densities pass a critical threshold (800 persons/km²), supporting Malthus’ hypothesis.
In the second Paper, we pay specific attention to the economic effect of resource (grazing, water and crop residue) scarcity measured in a traveling time and shadow cost on labor for crop farming and crop food production. The analysis in this paper was conducted in order to test the hypothesis that increasing time spent on searching for grazing, water and collecting straw has a negative effect on crop farm labor time and crop farm production based on non-separable household model. Our results favor the hypothesis of a negative relationship between labor input to crop farming and resource scarcity. In aggregate, the findings confirm that reducing time spent looking for water and animal feed increases food production. Likewise, our results show that moderate significant difference in crop output value between male and female resulting from a resource scarcity. The quantile regression also proved that the effects of these scarce resources are heterogeneous.
Paper 3 focus on the link between animal resource scarcities measured in a traveling time and shadow cost and welfare and food security drawing on a separable farm household model. The theoretical prediction that resource scarcity adversely affects household per capita food consumption expenditure (welfare) and food security, as predicted by the downward spiral hypothesis was tested using a double log IV 2SLS for the case of welfare and probit model in the case of food security. In aggregate, our principal findings confirmed that resource scarcity affect household welfare and food security adversely and effect is not uniform across the food income groups.
Paper 4 assess the effects of production risk and time preference on animal feeding practice use and feeding choice. Using the theoretical framework suggested by Antle (1987) and Koundouri et al. (2006), the author shows production risk to be the main determinants of stall feeding adoption and its full application using estimated moments of the value of milk production. It further considers discount factor and animal shock exposure into account as key factors of SF adoption and its application. Our empirical analysis revealed that production risk and time preferences are key determinant of SF adoption and full year application.Denne avhandlingen analyserer storfelandbruk i nordlige Etiopia for å i) teste hypotesene til Boserup og Malthus knyttet til hvordan befolkningspress påvirker intensivering av landbruket, og ii) den nedgående spiralhypotesen som sier at fattige er tvunget til å overforbruke de begrensede ressursene for å overleve, og dette gjør dem enda fattigere. Avhandlingen består av fire selvstendige artikler. Den første studerer virkningen av varierende befolkningspress/tetthet på i) bruksstørrelse og antall storfe pr bruk, ii) bruk av moderne innsatsfaktorer og iii) produksjon pr bruk. Analysen består av recursive regresjoner med en kontrollfunksjon tilnærming basert på et datasett bestående av 518 tilfeldig utvalgte bruk. Analysen viser at både Multhusiske og Boserupske faktorer har betydning. Befolkningspress påvirker både etterspørsel etter innsatsvarer og produksjon. Konsistent med Malthus’ teori så bidrar høyt befolkningspress til mindre bruksstørrelse og flere storfe pr bruk. Som predikert av Boserup’s teori øker bruken av innsatsvarer og produksjon med økende befolkningspress opp til en øvre grense for befolkningstetthet (800 personer/km2 ), men avtar over dette i tråd med Malthus’ teori.
I artikkel 2 studeres den økonomiske effekten av ressursknapphet (beiteareal, vann og halm fra kornproduksjon) målt i transporttid og skyggekostnader på arbeidsbehovet i planteproduksjon. Artikkelen forsøker å teste hypotesen at økende tid brukt på å skaffe fôr og vann har en negativ effekt på tid brukt i planteproduksjon og på produsert mengde. Resultatene påviser en negative sammenheng mellom ressursknapphet og arbeidsforbruk i planteproduksjon.
I artikkel 3 studeres sammenhengen mellom ressursknapphet i tilknytning til storfehold målt i form at tidsbruk og skyggekostnader og virkning på matvaresikkerhet (selvforsyning med mat). En negativ sammenheng ansees som en test av hypotesen om en negativ spiral i ressurbruk og produksjon over tid. Den økonometriske analysen indikerer at en slik sammeheng eksisterer med det er betydelig lokal variasjon mellom inntektsgrupper.
Artikkel 4 studerer effektene av produksjonsrisiko og tidspreferanser på fôringsregimet for storfe, inklusive valg av fôrslag. Basert på det teoretiske rammeverket til Antle (1987) og Koundouri et al. (2006) vises det at produksjonsrisiko er den viktigste faktoren som fører til adopsjon av nullbeiting. Studien ser også på hvordan tidspreferanser og sjokk som direkte påvirker storfehusholdet påvirker adopsjon av nullbeiting. Det vises at også tidspreferanser har betydning for adopsjon av nullbeiting.Mekelle University ; NORA
Environmental flow assessment and implications on sustainability of aquatic ecosystems in Ethiopia: A literature review on global and national evidences
No full textAs part of water resources management policy, water resources projects undertake environmental flow assessments (EFA) to determine how much water should be maintained or released to the downstream part of rivers to protect the health of aquatic and riparian ecosystems and societal wellbeing. In Ethiopia, EFA is being undertaken mostly in relation to dam projects. Most of dam projects in Ethiopia consider the 95% exceedance probability flow (Q95) as acceptable for downstream releases, which does not consider the variable and dynamic nature of rivers or the impacts on societal livelihoods dependent on ecosystem services. This paper aims to explore the application of EFA in Ethiopia based on global and national experiences. The paper begins with an overview of the water resources and biodiversity that need protection; second, systematic review of the current status of application of EFA methodologies in Ethiopia; and finally, the main types of environmental flow methodologies available globally that can be utilized in different parts of the country were explored, with emphasis on projects and research endeavors. It is found that environmental flow is strongly considered in Ethiopia, which is critical as the country is a custodian to precious aquatic and riparian biodiversity resources which have national and global importance. However, it is found also that there is little research on the topic for advising appropriate EFA methodology application in Ethiopia. Thus, it is suggested a holistic approach of environmental flow assessment that can entertain all other types of methods in tropical highland rivers.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Water Resource
