Authors:Markos F. Yimer, Tsegaye G. Ayele Pages: 109 - 130 Abstract: The Dirichlet and Neumann boundary value problems for the linear second-order scalar elliptic differential equation with variable coefficients in a bounded two-dimensional domain are considered. The right-hand side the PDE belongs to H´1 pΩq or Hr ´1 pΩq, when neither classical nor canonical conormal derivatives of solutions are well defined. The two-operator approach and appropriate parametrix (Levi function) are used to reduce each of the problems to two different systems of two-operator boundary-domain integral equations (BDIEs). Although the theory of BDIEs in 3D is well developed, the BDIEs in 2D need a special consideration due to their different equivalence properties. As a result, we need to set conditions on the domain or on the associated Sobolev spaces to ensure the invertibility of corresponding parametrix-based integral layer potentials and hence the unique solvability of BDIEs. The equivalence of the two-operator BDIE systems to the original problems, BDIE system solvability, solution uniqueness/nonuniqueness, and invertibility BDIE system are analyzed in the appropriate Sobolev spaces. It is shown that the BDIE operators for the Neumann BVP are not invertible, and appropriate finite-dimensional perturbations are constructed leading toinvertibility of the perturbed operators. PubDate: 2023-11-22 DOI: 10.4314/sinet.v46i2.1 Issue No:Vol. 46, No. 2 (2023)
Authors:Kibru Ababu Agonafir , Bahru Tsegaye Leyew Pages: 131 - 145 Abstract: In this article, we introduce a new concept of generalized F -contraction of nonlinear multivalued mappings and establish conditions for the existence of common fixed points of such mappings in the framework of bi- b-metric spaces. These findings combine, generalize, and expand on current and classic analogous findings in the literature. PubDate: 2023-11-22 DOI: 10.4314/sinet.v46i2.2 Issue No:Vol. 46, No. 2 (2023)
Authors:Zebene Girma Tefera , Samuel Asefa Fufa Pages: 146 - 153 Abstract: This paper studies a special case of group divisible designs (GDDs) called 3-GDDs, which were defined by extending the definitions of a group divisible designs and a t-design. In particular, the paper looks at a 3-GDD(n, 4, 5; μ1, μ2) with 4 groups and block size 5. Necessary conditions for the existence of such GDDs are developed, the non-existence of a 3-GDD(n, 4, 5; μ1, 0) is proved and several specific instances of non-existence are given. PubDate: 2023-11-22 DOI: 10.4314/sinet.v46i2.3 Issue No:Vol. 46, No. 2 (2023)
Authors:Tekie F. Tesfamichael Pages: 154 - 162 Abstract: Early Miocene sedimentary layersfrom the Mush Valley in the Ethiopian Highlands located northeast of Addis Ababa preserve compressed fossil leaves and seeds with abundant organic matter in carbonaceous lacustrine shales. Fossil leaf morphotypes, preserved in those sediments, allow compilation of data and provide information on species richness and species relative abundance without the need for lengthy investigation to determine their taxonomic identity. Moreover, identification of fossil plants with respect to their nearest living relatives provides additional data critical for understanding their phylogenetic history, paleoclimate, and concentration of atmospheric CO2. Here a previously unnamed taxon from the Mush Valley site was described; the taxon has a distinctly acrodromous primary venation, a pulvinus base, brachyparacyticstomatal complexes, and a suite of other characters of higher order venation and epidermal cells. The comparison of venation patterns and cuticular features among the fossil leaves and herbarium leaves using categorical variables shows that the fossil shares several characters with trinerved species in the genus Scolopia, but does not share all characters with any living species. Therefore, an extinct species found in the genus Scolopia (Scolopieae, Salicaceae) is described; the genus Scolopia is found today in Madagascar, the Solomon Islands, the Comoros, Southeast Asia, and eastern Australia. Two species of Scolopia occur today in Ethiopia, but these appear distantly related to the fossil based upon their pinnate, rather than acrodromous, primary venation. The fossil leaves are 21.73 ± 0.03 million years old, based upon 206Pb/238U geochronology, which can provide a precise date pointfor phylogenetic analysis. The taxonomic identification of this fossil leaf has important implication for reconstructing concentration of atmospheric CO2 and paleo temperature of the time and hence, to understand the response of plants to the early Miocene global warming. PubDate: 2023-11-22 DOI: 10.4314/sinet.v46i2.4 Issue No:Vol. 46, No. 2 (2023)
Authors:Lemlem Hagos, Million Meshesha, Solomon Atnafu , Solomon Teferra Pages: 163 - 175 Abstract: In this article, exploratory research is conducted to analyze statistical overlap across Amharic and Tigrigna at different level of abstraction, namely, word level, CV syllable level, and at phoneme level. Amharic and Tigrigna are among the most widely spoken Ethiosemitic languages in Ethiopia, yet under resourced to be fully integrated into TTS applications that assist oral society in their day-to-day activities. Text to speech research requires linguistic resources involving intensive text analysis and acoustic resources that involve digital signal analysis. TTS researches for Ethiosemitic languages have been explored on monolingual basis which require fragmented research activities towards the resource intensive task. Investigating the level of overlap for Amharic and Tigrigna gives an insight to reuse shared acoustic and linguistic resources across these languages and reduce duplication of effort in the process of designing higher level applications such as TTS. According to our statistical analysis, Amharic and Tigrigna share 86.36% at phonemic level, 85.93% at CV syllable level, and encouraging level of overlap at the word level. The extent to which these languages overlap at different level of abstraction implies the opportunity to reduce duplication of effort in the design and development of bilingual and multilingual TTS for Ethiosemitic polyglots. PubDate: 2023-11-22 DOI: 10.4314/sinet.v46i2.5 Issue No:Vol. 46, No. 2 (2023)
Authors:Tamenu Abera Tamenu Abera , Mogessie Ashenafi Mogessie Ashenafi Pages: 176 - 187 Abstract: : Street foods are common in in Addis Ababa. The city administration considers the business as informal and illegal. However, street food operation creates significant self-employment opportunities. Moreover, it markedly contributes to the food security of low-income consumers and vendors. The food security status, food safety knowledge and practice of 160 stationary street food vendors were assessed around Mexico Square, Addis Ababa. A detailed site observation was made around vending sites. Household food insecurity experience and food safety KAP of vending households was assessed using close-ended standard questionnaires. Job-specific interviews were made on street food operation with key informants from among woreda officials and consumers. Quantitative data was analyzed using descriptive statistics and opinions of key informants were described. About 72% of the street food vendors were female. Over 90% were adolescents or young adults and 30% had more than three children. About 71% of the vendors were either moderately or severely food insecure. Vendors had good knowledge (81%), moderate attitude (74%) but very poor practice (14%) in food safety. Street food vending was the only source of affordable meals to low-income groups in the study area. Meals were served and consumed immediately after cooking minimizing food safety risks. As street food vending creates economic and physical access to the low-paid urban poor and is a livelihood to poor families, it may be useful to recognize its positive role in mitigating food insecurity. Government control on food safety compliance, allocation of vending zones, and giving training to street food vendors could improve safety of street foods. PubDate: 2023-11-22 DOI: 10.4314/sinet.v46i2.6 Issue No:Vol. 46, No. 2 (2023)
Authors:Workia Ahmed , Tileye Feyissa , Kassahun Tesfaye, Sumaira Farrakh Pages: 188 - 202 Abstract: Date palm (Phoenix dactylifera L.) is one of the oldest fruit bearing perennial trees classified under the genus of Phoenix in Arecaceae (Palm) family. The natures of date palms with their long productivity have an indispensable socio-economicsignificance and contributions in agricultural sustainability. The date palm is a food and income source for societies particularly in the desert and also it has medicinal, cultural, ecological and environmental values. Date palms are dioecious with a wide range of phenotypic variations. Therefore, evaluation of date palm cultivars using morphological characters at regional as well as global level is critically necessary for sustainable utilization of itsgenetic resources as well as for genetic improvement and conservationprograms. The aim of this study is to assess the phylogenetic relationships of ate palms date palm cultivars cultivated at Melka Werer research centre. A total of 45 morphological traits were used to assess phylogenetic relationships of eleven date palm cultivars. All traits showed mean variations amongthe cultivars.Principal component analysis on the first component revealed 37% variation in vegetative and reproductive traits data combined together and 29% and 32% of variations was observed in separate vegetative and reproductive morphological traits data respectively. Among 45 morphological traits 43 traits exhibited significant differences at p <0.05 inanalysis of variance and also 23 traits showed significant variances at p <0.05 inhomogeneity of variance analysis among cultivars. Besides, dendrograms were constructed based on combined vegetative and reproductive traitsdataand in separatevegetative and reproductive traits data and showed the genetic relationships between date palm cultivars.Generally, this study clearly display the phenotypic variations between cultivars and also the resultis important as baseline for documenting and further agronomic traits studies of date palm cultivars particularly in Ethiopia. PubDate: 2023-11-22 DOI: 10.4314/sinet.v46i2.7 Issue No:Vol. 46, No. 2 (2023)
Authors:Demissie Gashu Walle Pages: 203 - 212 Abstract: Motivation can be seen as a major factor in improving physical exercise behavior among people. Evaluating the motivational of university students towards physical fitness workout is important to implement intervention strategies’ to increase their motivationlevel for their personal development and achievement of individual goals.This study aimed to assess university first-year undergraduate students' motivations for engaging in physical fitness workout and how those motivations related to contextual factors. The study used a cross-sectional survey design consisted of 323 sample students at Bahir Dar University. The majority age of the students (n= 216, 66.9%) were 20 years old. The adapted Exercise Self-Regulation Questionnaire (SRQ-E) was used to measure the motivation for physical fitness workout. The results were analyzed using descriptive statistics and t tests. The results show that overall mean of students’ motivation for physical fitness workout was below the average (2.85). The mean scores of most few motivational variables show significant statistical difference across the students religion, and residential status (p<.05).As far as major field was concerned, there was a statistically significant difference between natural and social science students in the two motivational variables: identified regulation and external motivation (p<.05,Cohen's d= -.123 & -.027). To understand the motivation of freshman students for physical fitness workout in universities, future research needs to consider the direct effect of some other contextual variables. PubDate: 2023-11-22 DOI: 10.4314/sinet.v46i2.8 Issue No:Vol. 46, No. 2 (2023)
Authors:Ameneshewa Tahlew , Jemal Abagissa , Aschenaki Taddese , Zeru Bekele Pages: 213 - 22 Abstract: The purpose of this study was to examine conflict management and resolution in Ethiopian Athletics Federation. Cross sectional survey design which incorporates both quantitative and qualitative methods was the research design of the study. The target population of the study was 284 and of these a sample of 166 respondents was selected using probability proportional sampling technique. Regarding the data collection instruments, questionnaires, interviews and document analysis were employed. The data obtained through questionnaires were analyzed using statistical tools such as frequency, standard deviation, and average. The finding of the study indicated that there were different causes and sources of conflicts in the federation. Informal relations, rent seeking and misinterpretation of rules and regulations are the major causes of conflicts. The gaps were also identified in the conflict management style and the time it takes to resolve. PubDate: 2023-11-22 DOI: 10.4314/sinet.v46i2.9 Issue No:Vol. 46, No. 2 (2023)
Open Access journal
