Modeling coronal magnetic field using spherical geometry: cases with several active regions

The magnetic fields in the solar atmosphere structure the plasma, store free magnetic energy and produce a wide variety of active solar phenomena, like flare and coronal mass ejections(CMEs). The distribution and strength of magnetic fields are routinely measured in the solar surface(photosphere). Therefore, there is considerable interest in accurately modeling the 3D structure of the coronal magnetic field using photospheric vector magnetograms. Knowledge of the 3D structure of magnetic field lines also help us to interpret other coronal observations, e.g., EUV images of the radiating coronal plasma. Nonlinear force-free field (NLFFF) models are thought to be viable tools for those task. Usually those models use Cartesian geometry. However, the spherical nature of the solar surface cannot be neglected when the field of view is large. In this work, we model the coronal magnetic field above multiple active regions using NLFFF extrapolation code using vector magnetograph data from the Synoptic Optical Long-term Investigations of the Sun survey (SOLIS)/ Vector Spectromagnetograph (VSM) as a boundary conditions. We compare projections of the resulting magnetic field lines solutions with their respective coronal EUV-images from the Atmospheric Imaging Assembly (SDO/AIA) observed on October 11, 2011 and November 13, 2012. This study has found that the NLFFF model in spherical geometry reconstructs the magnetic configurations for several active regions which agrees with observations. During October 11, 2011 observation, there are substantial number of trans-equatorial loops carrying electric current.Comment: 3 Figures, Submitted to Astrophysics and Space Science Journa

Petrographic and Geochemical Study of Low Grade Metamorphic Rocks around Negash with Reference to Base Metal Mineralization and Groundwater Quality, Tigray, Northern Ethiopia

Petrographic and geochemical data of Upper Proterozoic, low grade metamorphic rocks (Tsaliet Group) in and around Negash is interpreted in this paper with their mineralization potential and influence on groundwater quality. Among the three types of metamorphic rocks, metavolcanics (MV), metavolcaniclastics (MVC) and metasediments (metapelites) (MP) are present in the study area. Metavolcanics are massive, non-foliated and show presence of relicts of plagioclase feldspar and pyroxenes set in a fine grained matrix. Metavolcaniclastics show presence of clasts set in a fine grained tuffaceous groundmass and indicate a significant compositional contrast between these, probably volcanic derived, groundmass and the clasts. The clasts vary in size and shape from angular, subrounded to rounded and even elliptical (due to shearing). Phyllite, the predominant lithounit of metasediments is composed of fine grained muscovite, quartz and chlorite with incipient foliation and at places well developed crenulations. Presence of chlorite together with poorly developed muscovite and biotite (rare) suggests low grade metamorphic conditions that prevailed in the area. Geochemical data of metavolcanics indicate variation in their composition from basalt to andesite. Metavolcaniclastics are relatively enriched in alkalis and silica and deficient in MgO compared to metavolcanics. Phyllite on the other hand is enriched in K2O and silica compared to metavolcanics. Development of chlorite, sericite and other minerals due to low grade metamorphism and hydrothermal alteration have modified the chemistry of the rocks particularly MgO by chlorite in phyllite. Shear zones are common in the rocks of the study area, trending N-S and showing presence of clasts with non-ideal tails, relatively higher amount of quartz veins, malachite stains, Cu anomalies and sericitisation. These stains and anomalies strongly suggest a shear zone-controlled copper mineralization. Island arc-setting, bimodal volcanism, intrusive granitic plutons and similar type of shear zone –controlled Zn-mineralization in the nearby Abrha Atsbha area indicate possible presence of a similar kind of mineralization elsewhere in the basement rocks around these plutons. Hydrogeochemical data indicate that groundwater is relatively fresh and among major elements Na, Ca and Mg show relatively higher values compared to K. Water from metasediments is relatively harder among others. Na though shows higher values compared to Ca and Mg does not indicate any particular trend. Ca and Mg concentrations are related to the mafic and plagioclase feldspar minerals. Among trace elements, iron, nickel and lead show relatively higher values compared to other analyzed elements. Fe and Ni are related to metavolcanics and metavolcaniclast, and Pb to metapelite. Key words: Low grade metamorphic rocks, Base metal mineralization, Petrography, Hydrogeochemistry, Negash, Ethiopi

Mediastinal Lipoblastoma: A Case Report and Review of literature

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Groundwater Suitability for Irrigation: a Case Study from Debre Kidane Watershed, Eastern Tigray, Ethiopia

The present paper tries to assess groundwater suitability for irrigation purpose in Debre Kidane Watershed (45.09 km2), northern Ethiopia. The goal was to evaluate the suitability of the groundwater for irrigation, examine the water types and to investigate possible long and short term impact on groundwater quality. Thirty six water samples each were collected in rainy and dry (irrigation) seasons from the active shallow hand dug wells. The well selection for detailed study and water sampling was done using stratified followed by random sampling technique. The number of wells selected for study is accounting 10% of the total available hand dug wells in the area. Parameters such as electrical conductivity (EC), pH, Total Dissolved Solids (TDS), temperature and other physical properties were recorded in the field. Major anions and cations (Ca2+, Mg2+, K+, Na+, CO32-, HCO3-, Cl-, SO42- and NO3-) were analyzed in the laboratory. Chemical data suggests that the water type in the area though varies from Mg-HCO3, Ca-HCO3, Mg-Cl, Na-HCO3 to K- HCO3, predominantly it is mixed cation-HCO3 type in the rainy season; and Ca-HCO3 (Piper diagram) and Na-HCO3 (Stiff diagram) in irrigation season. Dominance of Na in irrigation season and increase in Sodium Absorption Ratio (SAR) are primarily due to possible increase of Na absorption in the soil replacing Ca. According to the guidelines for irrigation water quality, the groundwater is suitable for irrigation with some minor exceptions. In rainy season, 89% of the samples fall under the water class “good” and 11% “permissible” whereas in irrigation season only 30% are classified as “good” and 70% under “permissible” class. Toxicity in terms of SAR and salinity though presently under control and there is no specific toxicity effect on vegetables and field crops, however, there are indications of their increase in due course of time if proper measures are not taken. Keywords: Groundwater, Irrigation, Salinity, SAR, Toxicity, Water quality, Hand dug well, Ethiopia

Hydrogeological Investigation and Groundwater Potential Assessment in Haromaya Watershed, Eastern Ethiopia

The paper assesses groundwater quality and productivity in Haromaya watershed, eastern Ethiopia. Continuous pumping test data, collected from seven boreholes was used to determine productivity of the aquifers. 14 water samples were tested for water quality. The aquifers on the basis of permeability, potential and extent of aquifers, are categorized into i) extended and shallow aquifers with intergranular porosity and permeability, and with moderate to high potential (alluvial and lacustrine sediments); ii) limited and shallow aquifers with fracture and/or karstic porosity and permeability, and with moderate potential (sandstone and limestone); and iii) limited and shallow aquifers with intergranular and fracture porosity and permeability, and with low potential (granite). On the basis of chemical data, the water is fresh except in lacustrine and swampy areas. HCO3-, Ca2+, Na+ and Mg2+ are the dominating ions in water from granite, sandstone and alluvium; and Cl and SO4 dominate in water from lacustrine sediments apart from HCO3-, Ca2+, Na+ and Mg2+. Areas suitable for groundwater development in the area are discussed. Keywords: Aquifer, Ethiopia, Groundwater potential, Haromaya, Hydrogeochemistry

Knowledge, attitude and practice of progestin-only emergency contraceptives among female students of Jimma Teachers Training College, Jimma, Ethiopia

Background: Emergency contraception (EC) is the safest strategy for prevention of unintended pregnancy following unsafe sex provided that users have sufficient knowledge & awareness of EC. Objective: The main objective of this study was to assess the knowledge, attitude, and practice of progestin-only emergency contraceptives. Methods: Retrospective cross-sectional study was conducted from February 16 to April 18, 2017, among students of Jimma teacher’s training college. Chi-square test was run to identify the association between variables. Variables with the critical value P<0.05 at CI of 95% were considered as statistically significant.Results: A total of 270 female students were involved in the study; of which 53.70% of them had knowledge about ECs. A significant association was found between knowledge on ECs & age distribution (p<0.001) and also the sexual activity of the participants (p=0.013).More than half of the respondents agreed that widespread use of ECs would increase the prevalence of HIV/ AIDS and other sexually transmitted diseases (STIs). Of the total study participants, 121 (44.81%) have used ECs and the utilization practice has a significant association with age distribution (p<0.001 and religion of the study participants (p=0.002).   Conclusion: Generally, nearly half of the study participants had knowledge about ECs and used EC at least once in their lifetime. Most of the students agreed that relying on EC pills and its accessibility would promote the spread of HIV/AIDS and STIs.  Funding: The study was conducted with the financial support of Jimma UniversityKeywords: Knowledge, emergency contraceptives, attitude, practic

Initiatives, Opportunities and Challenges in Shallow Groundwater Utilization: a Case Study from Debrekidane Watershed, Hawzien Woreda, Tigray Region, Northern Ethiopia

This paper assesses the opportunities and challenges of household irrigation practices that use groundwater as source in an area in Debrekidane watershed (45.1 km2), Tigray region, northern Ethiopia. It was done by evaluating the recharge and discharge potential of the aquifers, different water harvesting recharge structures and the impact of the intervention on the livelihood of the households. The recharge and discharge potential of the wells were determined from the pumping tests conducted on selected wells. The potential of different recharge structures were determined by evaluating size and nature of their construction. Impact of the intervention on livelihood of the household was assessed through developed semi-structure questionnaires, and by conducting focal group, individual, formal and informal discussions. There are about 360 hand dug wells in the study area getting recharged through the water harvesting structures and directly from rainfall. The numbers of beneficiaries are 326, out of which 5 % are women headed households. Nine per cent of the owners have double hand dug wells. The major opportunities identified in the area include planting variety of new trees, plants, and cultivating of highly valued crops, improvement of the households feeding habits and generation of regular income; and introduction and adoption of water lifting technologies. At the same time spacing and sliding of walls of the hand dug wells, simultaneous production of similar type of vegetable crops by many farmers, wastage of lands due to many wells and the waste debris material, maintenance of water lifting technology, water scarcity; and proper water utilization are some of the major challenges that are faced in the area. Though intervention has changed the situation from meager to significant production, the benefits can further be enhanced by overcoming the identified challenges

Pattern of Fatal Injuries in Addis Ababa, Ethiopia: A One-year Audit

Background: Injury continues to account for a large number of clients attending emergency department in Addis Ababa. Reliable information on causes of death is essential to the development of health policies for prevention and control. The aim of this atudy was to identify the pattern and common causes of fatal injuriesMethods: This is prospective study analyses autopsy data related to fatal injuries handled by Menilik II Hospital between July1, 2006 –June 30, 2007. (Sene 24, 1998 - Sene 23, 1999)Results: A total of 2107 cases were analyzed. The victims were mostly male and the most vulnerable age group was found to be 15-44 years. Accidents versus homicide and accident versus suicide ratio was 1.8:1 and 5:1 respectively. Road traffic accidents were the most frequent causes of accident related death. Main means of homicide was hit by blunt or sharp object or firearm. More than 90% of victims who committed suicide use hanging or poisoning.Ninety percent of deaths occur with in 24 hours of the injury and only 105 (5%) died from the second day on wards. Eighty one percents of this patients had never received any medical care (either pre-hospital or hospital level).Conclusion: Road traffic accidents accounted for most causes of injury related deaths. Significant proportion of patients had no access to emergency medical care. The findings strongly suggest that more aggressive, regulatory, educational, and rapid emergency treatment is necessary to address the large number of injury related death