Spatio-temporal land use/cover dynamics and its implication for sustainable land use in Wanka watershed, northwestern highlands of Ethiopia

Long-term land use and land cover (LULC) dynamics information is essential to understand the trends and make necessary land management interventions, such as in the highlands of Ethiopia. This study analyzed six decades of LULC dynamics of Wanka watershed, Northwestern Ethiopian highlands. Two sets of aerial photographs (1957 and 2017), SPOT 5 and sentinel satellite imageries were analyzed. In addition, key informant interviews, focus group discussions and field observations were used to identify the drivers and impact of LULC change. It was found that cultivated and rural settlement land (CRSL), bare land, and urban built up area have been continuously expanded at the expenses of mainly forest and shrub lands. Over the entire study period (1957–2017) while the bare land and CRSL have increased by about 59% and 20% respectively, forest and shrub lands have declined by 59% and 57% respectively. Urban built up area has also expanded. The impact of popula- tion pressure and expansion of CRSL land were considerable. The trend of LULC dynamics in the study watershed implies adverse impact on the quality and quantity of the land resource. Hence, appropriate land use planning and strategies that reduce expansion of cultivated land need to be practiced

Longitudinal river zonation in the tropics: examples of fish and caddisflies from endorheic Awash river, Ethiopia

Primary Research PaperSpecific concepts of fluvial ecology are well studied in riverine ecosystems of the temperate zone but poorly investigated in the Afrotropical region. Hence, we examined the longitudinal zonation of fish and adult caddisfly (Trichoptera) assemblages in the endorheic Awash River (1,250 km in length), Ethiopia. We expected that species assemblages are structured along environmental gradients, reflecting the pattern of large-scale freshwater ecoregions. We applied multivariate statistical methods to test for differences in spatial species assemblage structure and identified characteristic taxa of the observed biocoenoses by indicator species analyses. Fish and caddisfly assemblages were clustered into highland and lowland communities, following the freshwater ecoregions, but separated by an ecotone with highest biodiversity. Moreover, the caddisfly results suggest separating the heterogeneous highlands into a forested and a deforested zone. Surprisingly, the Awash drainage is rather species-poor: only 11 fish (1 endemic, 2 introduced) and 28 caddisfly species (8 new records for Ethiopia) were recorded from the mainstem and its major tributaries. Nevertheless, specialized species characterize the highland forests, whereas the lowlands primarily host geographically widely distributed species. This study showed that a combined approach of fish and caddisflies is a suitable method for assessing regional characteristics of fluvial ecosystems in the tropicsinfo:eu-repo/semantics/publishedVersio

Incoherent scatter radar studies of electron precipitation

Abstract In the studies presented in this thesis, we use the EISCAT UHF incoherent scatter radar (ISR) to study electron precipitation. A new ISR data analysis technique called BAFIM (BAyesian FIltering Module) is developed to calculate plasma parameters (electron density, electron temperature, ion temperature and line of sight ion velocity) with high time and range resolutions from incoherent scatter radar autocorrelation function (ACF) data. BAFIM adds properties of the so-called full-profile analysis to the standard EISCAT data analysis tool, GUISDAP, and extends the concept of full-profile analysis from range direction to both range and time. BAFIM-fitted electron density is used to study a rapidly varying electron precipitation event with high time resolution (4 s). Using a method called ELSPEC, differential number fluxes of precipitating electrons are inverted from electron density altitude profiles measured along the geomagnetic field line by the EISCAT UHF incoherent scatter radar. We show that the raw electron density, that was previously used in high time resolution works, may significantly underestimate the true electron density, when auroral electron precipitation heats the electron gas. The bias affects also electron energy spectra inverted from the raw density profiles, as well as auroral powers and field-aligned currents integrated from the spectra. Temporal variations of the auroral power derived from the fitted electron density show a very good agreement with variations of auroral emission intensity at 427.8 nm. Using more than 20 years of EISCAT UHF radar data, we study statistical characteristics of 1–100 keV electron precipitation at 66.7° magnetic latitude over Tromsø, Norway. Peak energy, auroral power and number flux of electron precipitation are derived from the radar data using the ELSPEC method. We find that 1–5 keV electrons dominate the precipitation from evening until morning in magnetic local time (MLT), while 5–10 keV electrons dominate the late morning hours (06–09 MLT). The average peak energy of precipitating electrons increases almost monotonically from evening (18 MLT) to morning hours (09 MLT). Energetic 30–100 keV electrons, which have been poorly covered in previous studies, are observed most frequently in the post midnight and morning hours. The 30–50 keV electrons dominate the energetic electron precipitation before 06 MLT, after which the 50–100 keV precipitation becomes dominant. Auroral power of the precipitating electrons is mostly in the 2–10 mWm−2 range at night (18–09 MLT), and average auroral powers measured in the pre-midnight hours are all larger than the corresponding measurements in the post-midnight hours. Auroral powers larger than 30 mWm−2 are observed most frequently in the pre-midnight side of the main auroral oval. Number flux of precipitating electrons has similar characteristics with auroral power. Occurrence rate of auroral electron precipitation as observed by the radar maximizes during declining phases of solar cycles 23 and 24, and during September and March equinoctial months. The occurrence frequency increases with MLT from evening to morning hours, partially due to motion of the auroral oval relative to the radar location. The analysis tools developed and used in this work can be applied to data analysis of the next-generation EISCAT_3D radar, which is currently under construction in Finland, Norway, and Sweden. The tools will allow the radar to reach its full potential, and reveal small-scale and rapidly varying auroral structures with unprecedented temporal and spatial resolutions. The techniques could be applied also to other ISR systems and ELSPEC could be further developed to enable its use for day-time observations of electron precipitation

Magnetic Island Localization for NTM Control by ECE Viewed Along the Same Optical Path of the ECCD Beam

Neoclassical tearing modes (NTMs) deteriorate high-pressure tokamak plasma confinement and can be suppressed by electron cyclotron current drive (ECCD). In order to obtain efficient suppression, the ECCD power needs to be deposited at the center of an NTM magnetic island. To enhance efficiency, this power also needs to be synchronized in phase with the rotation of the island. The problem is that of real-time detection and precise localization of the island(s) in order to provide the feedback signal required to control the ECCD power deposition area with an accuracy of 1 to 2 cm. Existing schemes based on mode location, equilibrium reconstruction, and plasma profile measurements are limited in positional and temporal accuracy and moreover will become very complex when applied to ITER. To overcome these limitations, it is proposed to provide the feedback signal from electron cyclotron emission (ECE) measurements taken along the identical line of sight as traced by the incident ECCD millimeter-wave beam but in reverse direction. Experiments on TEXTOR have demonstrated a proof of principle. These measurements motivate the further development and the implementation of such an ECCD-aligned ECE system for NTM control in larger fusion machines. Possible implementation of such a system on ASDEX-Upgrade, based on waveguides equipped with a fast directional switch, is presented in this paper. Possible further development for ITER is also discussed

Best practices for colony management: a neglected aspect for improving honey bee colony health and productivity in Africa

Apiculture has a well-recognized role in enhancing food security by pollination services around the globe. Besides, apiculture is an extremely valuable income-generating and job-creating activity for millions of men, women, and youths across Africa through trade of hive products, especially honey. However, the yields of honey and other hive products are apparently below the optimum in most African countries. In this review, we discuss the characteristics of the local honey bee subspecies and current apicultural practices in relation to the factors that can potentially influence colony productivity. We highlight some potential factors affecting colony management and productivity and discuss research gaps that need to be addressed in order to improve the profitability and the sustainability of apiculture on a large scale in Africa.</p

Single-dose tafenoquine to prevent relapse of Plasmodium vivax malaria

Treatment of Plasmodium vivax malaria requires the clearing of asexual parasites, but relapse can be prevented only if dormant hypnozoites are cleared from the liver (a treatment termed "radical cure"). Tafenoquine is a single-dose 8-aminoquinoline that has recently been registered for the radical cure of P. vivax.; This multicenter, double-blind, double-dummy, parallel group, randomized, placebo-controlled trial was conducted in Ethiopia, Peru, Brazil, Cambodia, Thailand, and the Philippines. We enrolled 522 patients with microscopically confirmed P. vivax infection (&gt;100 to &lt;100,000 parasites per microliter) and normal glucose-6-phosphate dehydrogenase (G6PD) activity (with normal activity defined as ≥70% of the median value determined at each trial site among 36 healthy male volunteers who were otherwise not involved in the trial). All patients received a 3-day course of chloroquine (total dose of 1500 mg). In addition, patients were assigned to receive a single 300-mg dose of tafenoquine on day 1 or 2 (260 patients), placebo (133 patients), or a 15-mg dose of primaquine once daily for 14 days (129 patients). The primary outcome was the Kaplan-Meier estimated percentage of patients who were free from recurrence at 6 months, defined as P. vivax clearance without recurrent parasitemia.; In the intention-to-treat population, the percentage of patients who were free from recurrence at 6 months was 62.4% in the tafenoquine group (95% confidence interval [CI], 54.9 to 69.0), 27.7% in the placebo group (95% CI, 19.6 to 36.6), and 69.6% in the primaquine group (95% CI, 60.2 to 77.1). The hazard ratio for the risk of recurrence was 0.30 (95% CI, 0.22 to 0.40) with tafenoquine as compared with placebo (P&lt;0.001) and 0.26 (95% CI, 0.18 to 0.39) with primaquine as compared with placebo (P&lt;0.001). Tafenoquine was associated with asymptomatic declines in hemoglobin levels, which resolved without intervention.; Single-dose tafenoquine resulted in a significantly lower risk of P. vivax recurrence than placebo in patients with phenotypically normal G6PD activity. (Funded by GlaxoSmithKline and Medicines for Malaria Venture; DETECTIVE ClinicalTrials.gov number, NCT01376167 .)