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Background In Ethiopia, cutaneous leishmaniasis is mainly caused by Leishmania ( L. ) aethiopica parasites and presents in three main clinical forms. It is still not clear if the host immune response plays a role in the development of these different presentations. Since neutrophils are likely to be one of the first immune cells present at the site of the sand fly bite, we set up an in vitro model of infection of neutrophils with L. aethiopica and assessed some of the main neutrophil effector functions: association with and internalisation of parasites, apoptosis and ROS production. We used three freshly isolated clinical isolates and one isolate that has been kept in culture for decades. Results Our results showed by flow cytometry that all four L. aethiopica isolates had the ability to associate with neutrophils. The three clinical isolates of L. aethiopica associated more efficiently with neutrophils than the long-term cultured L. aethiopica. At 18 h, two distinct populations of neutrophils were identified that associated with L. aethiopica , CD15 high and CD15 low neutrophils. Confocal microscopy demonstrated that all isolates can be internalised. Our results also showed that all parasites induced apoptosis in L. aethiopica -associated neutrophils. Moreover, our results showed that after 2 h, L. aethiopica -associated neutrophils upregulated their production of ROS, but to a greater extent with the long-term cultured L. aethiopica . After 18 h of incubation, CD15 low parasite + showed an impaired ability to produce ROS compared to CD15 high parasite + . Conclusions Using this in vitro model, our results show that different L. aethiopica parasite isolates, most notably long-term cultured parasites, had differential effects on neutrophil effector functions. Graphical Abstract

While the formation of equatorial electrojet (EEJ) and its temporal variation is believed to be fairly well understood, the longitudinal variability at all local times is still unknown. This paper presents a case and statistical study of the longitudinal variability of dayside EEJ for all local times using ground-based observations. We found EEJ is stronger in the west American sector and decreases from west to east longitudinal sectors. We also confirm the presence of significant longitudinal difference in the dusk sector pre-reversal drift, using the ion velocity meter (IVM) instrument onboard the C/NOFS satellite, with stronger pre-reversal drift in the west American sector compared to the African sector. Previous satellite observations have shown that the African sector is home to stronger and year-round ionospheric bubbles/irregularities compared to the American and Asian sectors. This study's results raises the question if the vertical drift, which is believed to be the main cause for the enhancement of Rayleigh–Taylor (RT) instability growth rate, is stronger in the American sector and weaker in the African sector – why are the occurrence and amplitude of equatorial irregularities stronger in the African sector?

Accurate estimation of global vertical distribution of ionospheric and plasmaspheric density as a function of local time, season, and magnetic activity is required to improve the operation of space‐based navigation and communication systems. The vertical density distribution, especially at low and equatorial latitudes, is governed by the equatorial electrodynamics that produces a vertical driving force. The vertical structure of the equatorial density distribution can be observed by using tomographic reconstruction techniques on ground‐based global positioning system (GPS) total electron content (TEC). Similarly, the vertical drift, which is one of the driving mechanisms that govern equatorial electrodynamics and strongly affect the structure and dynamics of the ionosphere in the low/midlatitude region, can be estimated using ground magnetometer observations. We present tomographically reconstructed density distribution and the corresponding vertical drifts at two different longitudes: the East African and west South American sectors. Chains of GPS stations in the east African and west South American longitudinal sectors, covering the equatorial anomaly region of meridian ∼37°E and 290°E, respectively, are used to reconstruct the vertical density distribution. Similarly, magnetometer sites of African Meridian B‐field Education and Research (AMBER) and INTERMAGNET for the east African sector and South American Meridional B‐field Array (SAMBA) and Low Latitude Ionospheric Sensor Network (LISN) are used to estimate the vertical drift velocity at two distinct longitudes. The comparison between the reconstructed and Jicamarca Incoherent Scatter Radar (ISR) measured density profiles shows excellent agreement, demonstrating the usefulness of tomographic reconstruction technique in providing the vertical density distribution at different longitudes. Similarly, the comparison between magnetometer estimated vertical drift and other independent drift observation, such as from VEFI onboard Communication/Navigation Outage Forecasting System (C/NOFS) satellite and JULIA radar, is equally promising. The observations at different longitudes suggest that the vertical drift velocities and the vertical density distribution have significant longitudinal differences; especially the equatorial anomaly peaks expand to higher latitudes more in American sector than the African sector, indicating that the vertical drift in the American sector is stronger than the African sector. Key Points Longitudinal vertical ionospheric density distributions difference Simultaneous observation of vertical drift and density distribution Validation of in situ density using tomographically imaged density

The study of variations in total solar irradiance (TSI) and spectral irradiance is important for understanding how the Sun affects the Earth’s climate. A data-driven approach is used in this article to analyze and model the temporal variation of the TSI and Mg  ii index back to 1947. In both cases, observed data in the time interval of the satellite era, 1978 – 2013, were used for neural network (NN) model-design and testing. For this particular purpose, the evolution of the solar magnetic field is assumed to be the main driver for the day-to-day irradiance variability. First, we design a model for the Mg  ii index data from F10.7 cm solar radio-flux using the NN approach in the time span of 1978 through 2013. Results of Mg  ii index model were tested using various numbers of hidden nodes. The predicted values of the hidden layer with five nodes correspond well to the composite Mg  ii values. The model reproduces 94% of the variability in the composite Mg  ii index, including the secular decline between the 1996 and 2008 solar cycle minima. Finally, the extrapolation of the Mg  ii index was performed using the developed model from F10.7 cm back to 1947. Similarly, the NN model was designed for TSI variability study over the time span of the satellite era using data from the Physikalisch-Meteorologisches Observatorium Davos (PMOD) as a target, and solar activity indices as model inputs. This model was able to reproduce the daily irradiance variations with a correlation coefficient of 0.937 from sunspot and facular measurements in the time span of 1978 – 2013. Finally, the temporal variation of the TSI was analyzed using the designed NN model back to 1947 from the Photometric Sunspot Index (PSI) and the extrapolated Mg  ii index. The extrapolated TSI result indicates that the amplitudes of Solar Cycles 19 and 21 are closely comparable to each other, and Solar Cycle 20 appears to be of lower irradiance during its maximum.

Issue Title: International Heliophysical Year 2007: Second European General Assembly, Italy | Third UN/ESA/NASA Workshop, Japan The AMBER array contains four magnetometers and spans across the geomagnetic equator from L of 1 to an L of 1.4. In addition to filling the largest land-based gap in global magnetometer coverage, the AMBER array will address two fundamental areas of space physics: (1) the processes governing electrodynamics of the equatorial ionosphere as a function of latitude (or L-shell), local time, longitude, magnetic activity, and season, and (2) ULF pulsation strength and its connection with equatorial electrojet strength at low/mid-latitude regions. Satellite observations show unique equatorial ionospheric structures in the African sector, though these have not been confirmed by observation from the ground due to lack of ground-based instruments in the region. In order to have a complete global understanding of equatorial ionosphere motions, deployment of ground-based magnetometers in Africa is essential. One focus of IHY is the deployment of networks of small instruments, including the development of research infrastructure in developing nations through the United Nations Basic Space Science (UNBSS) Small Instrument Array. Therefore, AMBER magnetometer array in partnership with parallel US funded GPS receivers in Africa will allow us to understand the electrodynamics that governs equatorial ionosphere motions. While AMBER routinely observes the F region plasma drift mechanism (E × B drift), the GPS stations will monitor the structure of plasma at low/mid-latitudes in the African sectors. In addition to new scientific discoveries and advancing the space science research into Africa by establishing scientific collaborations between scientists in the developing and developed nations, the AMBER project also contributes to developing the basic science of heliophysics through cross-disciplinary studies of universal process. This includes the creation of sustainable research/training infrastructure within the developing nations (Africa). [PUBLICATION ABSTRACT]

NeQuick 2 ionospheric empirical model depends on global ionospheric coefficients that are estimated from unevenly distributed ionosonde measurements. In regions, like Africa, where very few observational data were available until recently, the model estimated the ionospheric peak parameters by interpolation. When one wants to employ the model to specify the ionosphere where very few data have been used for model development, the performances of the model need careful validation. This study investigates the performances of NeQuick 2 in the East African region by assisting the model with measurements from a single Global Positioning System (GPS) receiver, which has been deployed recently. This can be done by first calculating an effective ionization level that drives NeQuick 2 to compute slant total electron content (sTEC) which fits, in the least square sense, with the measurements taken from a single GPS receiver. We then quantify the performances of NeQuick 2 in reproducing the measured TEC by running the model at four other locations, where GPS stations are available, using the same effective ionization level that we calculated from a single GPS station as a driver of the model. Finally, the performances of the model before and after data ingestion have been investigated by comparing the model results with the experimental sTEC and vertical TEC (vTEC) obtained from the four test stations. Three months data during low solar activity conditions have been used for this study. We have shown that the capability of NeQuick 2, in describing the East African region of the ionosphere, can be improved substantially by data ingestion. We found that the model after ingestion reproduces the experimental TEC better as far as about 620 km away from the reference station than that before adaptation. The statistical comparisons of the performances of the model in reproducing sTEC before and after ingestion are also discussed in this study. Key Points Data ingestion can be a means to optimize the input parameter of NeQuick 2 NeQuick 2 after adaptation with one receiver data performs better for wider area The ability of ionization level in driving NeQuick 2 decreases with distance

Previous studies utilizing the Global Positioning System (GPS) receivers aboard Jason satellites have performed measurements of plasmasphere electron content (PEC) by determining the total electron content (TEC) above these satellites, which are at altitudes of about 1340 km. This study uses similar methods to determine PEC for the Jason-2 receiver for 24 July 2011. These PEC values are compared to previous determinations of PEC from a chain of ground-based GPS receivers in Africa using the SCORPION method, with a nominal ionosphere–plasmasphere boundary at 1000 km. The Jason-2 PECs with elevations greater than 60∘ were converted to equivalent vertical PEC and compared to SCORPION vertical PEC determinations. In addition, slant (off-vertical) PECs from Jason-2 were compared to a small set of nearly co-aligned ground-based slant PECs. The latter comparison avoids any conversion of Jason-2 slant PEC to equivalent vertical PEC, and it can be considered a more representative comparison. The mean difference between the vertical PEC (ground-based minus Jason-2 measurements) values is 0.82 ± 0.28 TEC units (1 TEC unit=1016 electrons m−2). Similarly, the mean difference between slant PEC values is 0.168 ± 0.924 TEC units. The Jason-2 slant PEC comparison method may provide a reliable determination for the plasmasphere baseline value for the ground-based receivers, especially if the ground stations are confined to only midlatitude or low-latitude regions, which can be affected by a non-negligible PEC baseline.

It has been well documented that the lunar tidal waves can modulate the ionospheric electrodynamics and create a visible influence on the equatorial electrojet (EEJ). The lunar tide influence gets intensified around noon, primarily during new and full Moon periods. However, the longitudinal, seasonal and solar cycle variability in the lunar tide influence on ionospheric current systems is not well understood yet. In order to investigate this, 17 years (1998–2014) of extensive magnetometer observations at four longitudinal sectors (western American, western and eastern African, and Asian) have been analyzed. All observations performed during magnetically active periods (Kp>3) have been excluded for this study to eliminate storm contributions to the geomagnetic field variation at the geomagnetic equator. This study's quantitative analysis revealed significant longitudinal, seasonal and solar cycle dependence of the lunar tide influence on the equatorial electrojet.

Hepatitis B virus (HBV) causes severe liver disease, such as hepatocellular carcinoma (HCC) and life-threatening liver disease. Hepatitis B virus infection is one of the most dominant public health problems these days. Therefore, this study aimed to determine the seroprevalence of HBV infection among patients attending Addis Alem Hospital, Bahir Dar, Northwest Ethiopia. A retrospective study was conducted from January to February 2019 on HBV registered from January 2016 to December 2018 for three years period. The presence of HBsAg in serum was detected using the One Step Cassette Style HBsAg test kit. Data were analyzed using SPSS version 20. Descriptive statistics were used to describe the characteristics of participants with HBV infection. Statistical association of the determinants with HBV infection was determined by the X test. In this study, a total of 2010 participants of HBsAg rapid test records in the laboratory logbook were included. The median age of women was 25 years. The overall seroprevalence of HBsAg was 78 (3.9%). There was a general increment of HBV infection from 2016 to 2018, X =7.52; P=0.023. Age (X =8.19; P= 0.042) and sex (X =37.77; P <0.001) were associated with HBsAg positivity. An intermediate seroprevalence of HBV infection was detected among participants in our study area. This figure raises significant public health concerns. Therefore, implementing strategies for routine screening of women for HBV and hospital attendants would be critical.

Measurements of equatorial thermospheric winds, temperatures, and 630 nm relative intensities were obtained using an imaging Fabry–Perot interferometer (FPI), which was recently deployed at Bahir Dar University in Ethiopia (11.6° N, 37.4° E, 3.7° N magnetic). The results obtained in this study cover 6 months (53 nights of useable data) between November 2015 and April 2016. The monthly-averaged values, which include local winter and equinox seasons, show the magnitude of the maximum monthly-averaged zonal wind is typically within the range of 70 to 90 ms−1 and is eastward between 19:00 and 21:00 LT. Compared to prior studies of the equatorial thermospheric wind for this local time period, the magnitude is considerably weaker as compared to the maximum zonal wind speed observed in the Peruvian sector but comparable to Brazilian FPI results. During the early evening, the meridional wind speeds are 30 to 50 ms−1 poleward during the winter months and 10 to 25 ms−1 equatorward in the equinox months. The direction of the poleward wind during the winter months is believed to be mainly caused by the existence of the interhemispheric wind flow from the summer to winter hemispheres. An equatorial wind surge is observed later in the evening and is shifted to later local times during the winter months and to earlier local times during the equinox months. Significant night-to-night variations are also observed in the maximum speed of both zonal and meridional winds. The temperature observations show the midnight temperature maximum (MTM) to be generally present between 00:30 and 02:00 LT. The amplitude of the MTM was  ∼  110 K in January 2016 with values smaller than this in the other months. The local time difference between the appearance of the MTM and a pre-midnight equatorial wind was generally 60 to 180 min. A meridional wind reversal was also observed after the appearance of the MTM (after 02:00 LT). Climatological models, HWM14 and MSIS-00, were compared to the observations and the HWM14 model generally predicted the zonal wind observations well with the exception of higher model values by 25 ms−1 in the winter months. The HWM14 model meridional wind showed generally good agreement with the observations. Finally, the MSIS-00 model overestimated the temperature by 50 to 75 K during the early evening hours of local winter months. Otherwise, the agreement was generally good, although, in line with prior studies, the model failed to reproduce the MTM peak for any of the 6 months compared with the FPI data.