SINET: Ethiopian Journal of Science

Information on the extinction of butterflies from Ethiopia

Emana Getu — Sat, 31 Aug 2024 00:00:00 +0000

Insects are said to be the most successful organism on earth because of their abundance. Auto of the 1.6+million animals known to science 1+ million are insects which are over two third of the described animals so far. Of over 30 insect orders, the order Lepidoptera is the 2^nd abundant order comprising about 180,000 insect species. Lepidoptera is divided in two major groups: butterflies and moths. The former species is diurnal, and the latter is nocturnal. The order comprises both beneficial and harmful insects. Some species from the butterflies’ group are good pollinators of plants. Butterflies are beautiful which as a result people use them to decorate their houses by hanging dead butterflies on the wall of their houses, which is very common in Europe. For tourist attraction some countries in Africa like Kenya have what is known as a butterfly farm. In Ethiopia up to recent time, most butterflies present in other tropical countries were abundantly present. In Addis Ababa and its surroundings where there are parks, forests, road sides and hotel compounds, it was very traditional to look at six to seven types of butterflies with different colors and sizes flies in the sky. However, this days you do not find any at all times of the year. Similar observations were made in Jimma, Adama, Bishoftu, Nekemete and Asosa. From this non-existence or diminishing number of butterflies, I concluded that butterflies extinction in Ethiopia become a reality. Hence, action should be taken to bring back butterflies to Ethiopia after compiling data on causes for the extinction.

Prediction of the effect of climate covariates on wind potential in Ethiopia

Bedanie Gemechu Bulty, Butte Gotu, Gemechis Djira, Joep Crompvoets — Sat, 31 Aug 2024 00:00:00 +0000

This study explores the interaction of climate covariates and spatial elements with wind speed in Ethiopia. It intends to extrapolate the potential spots of wind at unobserved spatial points using a meteorological dataset. We applied a combined dynamic spatial panel autoregressive random effects model with a spatial weight of inverse quartile separation distances of locations. This spatial weight outperforms the other spatial weights to capture spatial dependence and gain efficient estimates. The result describes that mean wind speed varies over the longitude range and latitude span, is influenced by climate covariates and fluctuates over the months of a year. Wind speed intensity is high along the central, eastern and northeastern parts of the region. It is also high in February, March, June, and July relative to September and October months. The evidence shows that wind speed is higher in summer and spring but relatively lower in winter and fall seasons. This implies that wind speed is high mainly after the rainy season ends and before it starts. The model estimates also show that mean wind speed is spatially correlated across neighboring stations and over temporal points. Particularly, the mean wind speed increases with altitude and temperature but decreases as precipitation increases. Sunshine fraction and relative humidity have negative effects, but their influence is not statistically significant with p=0.2496 and p=0.4484 respectively. In conclusion, the methods are recommended for the prediction of data that exhibits a stochastic process.

The Impact of Organizational Culture on Information Security Policy Compliance

Kibrom Ejigu, Mikko Siponen , Tilahun Muluneh — Sat, 31 Aug 2024 00:00:00 +0000

The objective of this study is to explore how organizational culture affects employee compliance with information security policies. To accomplish this goal, the authors developed a theoretical model and collected survey data from employees who work in organizations that have information security policies. We employed a quantitative survey research approach. We conducted our study at the commercial bank of Ethiopia (CBE). The collected data was analysed using analysis of moment structures (Cardoso and Ramos) software. The findings show that organizational culture significantly affects employee compliance with information security policies. Additionally, the study emphasizes the importance of considering the dominant organizational culture when trying to embed an information security policy. The contribution of this study lies in providing empirical evidence of the influence of organizational culture on information security compliance. To limit the scope of the study, the sample used in this research focuses only on organizational factors in Ethiopia. It is recommended that future studies be conducted in other countries to validate the results and ensure the generalizability of the findings. Practically speaking, creating a culture that supports information security practices is crucial for organizations, as technical and management measures alone cannot fully address the human aspect of information security. To better understand and enhance organizational behaviour regarding information security, companies should examine their organizational culture and how it impacts the effectiveness of implementing information security policies.

Theoretical Investigation of Thermoluminescence in the Presence of Thermally Disconnected Deep Traps

Nebiyu Gemechu, Tamirat Abebe, Kebede Shogile, Solomon H/Mariam, Shimelis Addisu — Sat, 31 Aug 2024 00:00:00 +0000

Thermoluminescence (TL) phenomenon is theoretically investigated using two active electron traps and one recombination center. The presence of one and two thermally disconnected deep traps (TDDTs) is taken in to account. The rate equations corresponding to this model are clearly formulated and the results are obtained using MTHEMATICA code. In particular, the variation of concentration of electrons in the active and thermally disconnected deep traps and the TL intensity are generated for various TL kinetic parameters such as activation energy and the frequency factor. The results show that the concentration of electrons in the active electron traps decrease with temperature while that in the TDDTs increase with temperature and approaches a constant. The generated TL glow curve (for E1 = 0.9 eV and E2 = 1 eV ) has two maxima. However, one broad glow curve with only one maximum is obtained when E1 and E2 are closer to each other. The profiles of the TL glow curves and the variation of concentration of electrons in the conduction band are the same except for their intensity.

Effects of Interfacial Layer on the Enhancement Factor of Spheroidal Metal/Dielectric Nanocomposites in Passive and Active Host Matrix

Tolasa Tamasgen Hirpha, Belayneh Mesfin Ali — Sat, 31 Aug 2024 00:00:00 +0000

We investigated the effects of depolarization factor (L) and metal fraction (p) on the local field enhancement factor (LFEF) of spheroidal metal/dielectric nanocomposites (NCs) with passive and active host matrix. The expressions of the electric potentials are obtained by solving Laplace’s equations in the quasistatic limit for spheroidal metal/dielectric NCs. The equation of LFEF in the host of spheroidal metal/dielectric NCs was then constructed by incorporating L and the Drude-Sommerfeld model into these formulas. The results show that, regardless of how each parameter changes or remains constant, the LFEF of the NCs has a single set of peaks in both the passive and active host matrix. The parameter L affects the LFEF curves, and the output peaks in both host media exhibit shifted symmetrical patterns. On the other hand, the media with interfacial layer (I) were significantly impacted when a field was applied to the metal/dielectric NCs medium, and the LFEF increased successively in the given frequency range with a single peak. Furthermore, in passive and active dielectric host media, the LFEF of the spheroidal shell of the NCs increased progressively with thickness. The LFEF peaks are significantly impacted by radius that was studied in both passive and active host media. We investigated that when p increases, the peak values of the LFEF in the shell structure rise. Additionally, by altering each parameter, it was possible to create an adjustable LFEF that could be utilized for optical detection, nonlinear optics, and optical sensing applications.

A survey of post-harvest handling practices and pest control measures in stored maize in western Ethiopia

Tsegab Temesgen , Emana Getu — Sat, 31 Aug 2024 00:00:00 +0000

This survey was conducted in western Ethiopia with 125 respondents using face-to-face interviews. Surveys evaluated farmers' post-harvest practices, losses from post-harvest handling, insecticide usage frequency, and management techniques for preventing storage pest infestations of maize. All of the farmers planted hybrid maize varieties. Post-harvest handling practices caused 24% of crop losses. Harvesting (2%), threshing (3%), transportation (2%), and storage (17%) were identified as major points of loss. Farmers employed several strategies to reduce pest damage in storage. Of these strategies, 81.6% of farmers used synthetic insecticides, with 31.62% using insecticides more than twice. In total, 5.6% of respondents used plants such as Croton macrostachyus and Lantana camara for controlling insects during storage, which were frequently mentioned. Sun drying, roofing, and regular cleaning were all adopted by 4% of farmers as cultural insect pest management strategies. About 6.4% of farmers used a combination of the above management tactics. Insect-resistant hybrid varieties are critical to developing and implementing sustainable pest management strategies. Local governments can develop more effective pest management strategies. The primary emphasis should be on IPM. This method is more efficient and long-lasting than single-method control strategies. This will help keep pest populations in check and minimize pesticide use.