Appearance and Precipitation Characteristics of High-Latitude Pulsating Aurora

Characteristics of pulsating aurora (PsA) at the equatorward part of the auroral oval have been well described in the literature by previous studies. We extend our knowledge on high-latitude PsA observations by analysing 68 PsA events from the optical observatory on Svalbard, at 75 degrees magnetic latitude. We found that the pulsating emission structures are particularly large and transient, they do not experience drift motion, or their drift motion cannot be traced. Our results show that the high-latitude PsA events relate to lower geomagnetic activity and weaker solar wind driving than the lower latitude PsA. The high-latitude PsA events also occur less frequently, which is in agreement with their association to lower-than-average geomagnetic activity. We further show that the ionospheric electron density values during high-latitude PsA events are low compared to the lower latitude PsA. This, together with the non-traceable nature of the pulsating emission structures, suggests that these events are strongly dominated by a sub-type called Amorphous Pulsating Aurora (APA). We therefore conclude that, unlike the lower latitude PsA events, the high-latitude PsA events are not likely to cause direct changes in the chemical composition of the mesosphere.Peer reviewe

Depression Among Epileptic Patients and its Association with Drug Therapy in Sub-Saharan Africa: A Systematic Review and Meta-Analysis.

BACKGROUND: Despite the high prevalence of epilepsy in sub-Saharan Africa and the established relationship between depression and epilepsy, the extent of comorbid epilepsy and depression in the region is still poorly understood. The objective of this systematic review and meta-analysis is to address this gap in the literature by determining the pooled prevalence of depression among epileptic patients in sub-Saharan Africa. METHODS: A systematic desk review and electronic web-based search of PubMed, Google Scholar, EMBASE, PsycINFO and the World Health Organization\u27s Hinari portal (which includes the SCOPUS, African Index Medicus, and African Journals Online databases) conducted from December 2, 2017 to February 30, 2018, identified peer-reviewed, original research articles and doctoral dissertations using pre-defined quality and inclusion criteria. Relevant data were extracted and descriptive summaries of the studies presented in tabular form. The I2 statistic was used to assess heterogeneity across studies. Funnel plot asymmetry and Egger\u27s tests were used to check for publication bias and the methodological quality of the included studies were assessed using the scale developed by Hoy and colleagues. The pooled prevalence of comorbidity at a 95% confidence interval (CI) was determined by applying a trim and fill analysis in a random-effects model. RESULTS: Our search identified 167 studies, of which 14 original research articles and two doctoral dissertations reporting on case-control and cross-sectional studies were eligible for inclusion in the final analysis. The pooled estimate of prevalence of depression among patients with epilepsy was 32.71% (95% CI: 25.50-39.91%). Regional sub-group analysis found that the pooled prevalence in East Africa was 34.52% (95% CI: 23.53-45.51%) and 29.69% (95% CI: 22.7-36.68%) in Southern and West Africa. The odds of depression among epileptic patients receiving polytherapy were 2.65 higher than in those receiving monotherapy (95% CI: 1.49-4.71, I2 = 79.1%, p \u3c 0.05). CONCLUSION: Our findings indicate high comorbidity in sub-Saharan Africa and suggest that it may be more prevalent there than elsewhere. Comorbidity is statistically associated with polytherapy in the studies reviewed. Given the high levels of comorbidity in the region, more attention should be paid to incorporating depression screening and treatment into existing epilepsy programs and to revising treatment guidelines on comorbid depression to reduce polytherapy

Appearance and Precipitation Characteristics of High-Latitude Pulsating Aurora

Characteristics of pulsating aurora (PsA) at the equatorward part of the auroral oval have been well described in the literature by previous studies. We extend our knowledge on high-latitude PsA observations by analysing 68 PsA events from the optical observatory on Svalbard, at 75° magnetic latitude. We found that the pulsating emission structures are particularly large and transient, they do not experience drift motion, or their drift motion cannot be traced. Our results show that the high-latitude PsA events relate to lower geomagnetic activity and weaker solar wind driving than the lower latitude PsA. The high-latitude PsA events also occur less frequently, which is in agreement with their association to lower-than-average geomagnetic activity. We further show that the ionospheric electron density values during high-latitude PsA events are low compared to the lower latitude PsA. This, together with the non-traceable nature of the pulsating emission structures, suggests that these events are strongly dominated by a sub-type called Amorphous Pulsating Aurora (APA). We therefore conclude that, unlike the lower latitude PsA events, the high-latitude PsA events are not likely to cause direct changes in the chemical composition of the mesosphere

5G Radio Access Networks Enabling Efficient Point-to-Multipoint Transmissions

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.[EN] The first release of 5th Generation (5G) technology from 3rd Generation Project Partnership (3GPP) Rel'15 has been completed in December 2018. An open issue with this release of standards is that it only supports unicast communications in the core network and Point-To-Point (PTP) transmissions in the Radio Access Network (RAN), and does not support multicast/broadcast communications and Point-To-Multipoint (PTM) transmissions, which are 3GPP system requirements for 5G applications in a number of vertical sectors, such as Automotive, Airborne Communications, Internet-of-Things, Media & Entertainment, and Public Warning & Safety systems. In this article, we present novel mechanisms for enhancing the 5G unicast architecture with minimal footprint, to enable efficient PTM transmissions in the RAN, and to support multicast communications in the Rel'15 core as an in-built delivery optimization feature of the system. This approach will enable completely new levels of network management and delivery cost-efficiency.This work was supported in part by the European Commission under the 5G Infrastructure Public Private Partnership project "5G-Xcast: Broadcast and Multicast Communication Enablers for the Fifth Generation of Wireless Systems" (H2020-ICT-2016-2 call, grant 761498). The views expressed here are those of the authors and do not necessarily represent the project.Säily, M.; Barjau, C.; Navrátil, D.; Prasad, A.; Gomez-Barquero, D.; Tesema, FB. (2019). 5G Radio Access Networks Enabling Efficient Point-to-Multipoint Transmissions. IEEE Vehicular Technology Magazine. 14(4):29-37. https://doi.org/10.1109/MVT.2019.2936657S293714

Observations of precipitation energies during different types of pulsating aurora

Pulsating aurora (PsA) is a diffuse type of aurora with different structures switching on and off with a period of a few seconds. It is often associated with energetic electron precipitation (>10 keV) resulting in the interaction between magnetospheric electrons and electromagnetic waves in the magnetosphere. Recent studies categorize pulsating aurora into three different types – amorphous pulsating aurora (APA), patchy pulsating aurora (PPA), and patchy aurora (PA) – based on the spatial extent of pulsations and structural stability. Differences in precipitation energies of electrons associated with these types of pulsating aurora have been suggested. In this study, we further examine these three types of pulsating aurora using electron density measurements from the European Incoherent Scatter (EISCAT) VHF/UHF radar experiments and Kilpisjärvi Atmospheric Imaging Receiver Array (KAIRA) cosmic noise absorption (CNA) measurements. Based on ground-based all-sky camera images over the Fennoscandian region, we identified a total of 92 PsA events in the years between 2010 and 2020 with simultaneous EISCAT experiments. Among these events, 39, 35, and 18 were APA, PPA, and PA types with a collective duration of 58, 43, and 21 h, respectively. We found that, below 100 km, electron density enhancements during PPAs and PAs are significantly higher than during APA. However, there are no appreciable electron density differences between PPA and APA above 100 km, while PA showed weaker ionization. The altitude of the maximum electron density also showed considerable differences among the three types, centered around 110, 105, and 105 km for APA, PPA, and PA, respectively. The KAIRA CNA values also showed higher values on average during PPA (0.33 dB) compared to PA (0.23 dB) and especially APA (0.17 dB). In general, this suggests that the precipitating electrons responsible for APA have a lower energy range compared to PPA and PA types. Among the three categories, the magnitude of the maximum electron density shows higher values at lower altitudes and in the late magnetic local time (MLT) sector (after 5 MLT) during PPA than during PA or APA. We also found significant ionization down to 70 km during PPA and PA, which corresponds to ∼200 keV of precipitating electrons.</p

Electron precipitation characteristics during isolated, compound, and multi-night substorm events

A set of 24 isolated, 46 compound, and 36 multi-night substorm events from the years 2008–2013 have been analysed in this study. Isolated substorm events are defined as single expansion–recovery phase pairs, compound substorms consist of multiple phase pairs, and multi-night substorm events refer to recurring substorm activity on consecutive nights. Approximately 200 nights of substorm activity observed over Fennoscandian Lapland have been analysed for their magnetic disturbance magnitude and the level of cosmic radio noise absorption. Substorm events were automatically detected from the local electrojet index data and visually categorized. We show that isolated substorms have limited lifetimes and spatial extents as compared to the other substorm types. The average intensity (both in absorption and ground-magnetic deflection) of compound and multi-night substorm events is similar. For multi-night substorm events, the first night is rarely associated with the strongest absorption. Instead, the high-energy electron population needed to cause the strongest absorption builds up over 1–2 additional nights of substorm activity. The non-linear relationship between the absorption and the magnetic deflection at high- and low-activity conditions is also discussed. We further collect in situ particle spectra for expansion and recovery phases to construct median precipitation fluxes at energies from 30 eV up to about 800 keV. In the expansion phases the bulk of the spectra show a local maximum flux in the range of a few keV to 10 keV, while in the recovery phases higher fluxes are seen in the range of tens of keV to hundreds of keV. These findings are discussed in the light of earlier observations of substorm precipitation and their atmospheric effects.publishedVersio

5G Radio Access Network Architecture for Terrestrial Broadcast Services

The 3rd Generation Partnership Project (3GPP) has defined based on the Long Term Evolution (LTE) enhanced Multicast Broadcast Multimedia Service (eMBMS) a set of new features to support the distribution of Terrestrial Broadcast services in Release 14. On the other hand, a new 5th Generation (5G) system architecture and radio access technology, 5G New Radio (NR), are being standardised from Release 15 onwards, which so far have only focused on unicast connectivity. This may change in Release 17 given a new Work Item set to specify basic Radio Access Network (RAN) functionalities for the provision of multicast/broadcast communications for NR. This work initially excludes some of the functionalities originally supported for Terrestrial Broadcast services under LTE e.g. free to air, receive-only mode, large-area single frequency networks, etc. This paper proposes an enhanced Next Generation RAN architecture based on 3GPP Release 15 with a series of architectural and functional enhancements, to support an efficient, flexible and dynamic selection between unicast and multicast/broadcast transmission modes and also the delivery of Terrestrial Broadcast services. The paper elaborates on the Cloud-RAN based architecture and proposes new concepts such as the RAN Broadcast/Multicast Areas that allows a more flexible deployment in comparison to eMBMS. High-level assessment methodologies including complexity analysis and inspection are used to evaluate the feasibility of the proposed architecture design and compare it with the 3GPP architectural requirements.Comment: 12 pages, 10 figures, 2 tables, IEEE Trans. Broadcastin

The Effect of Disclosure on Adherence to Antiretroviral Therapy Among Adults Living with HIV in Ethiopia: A Systematic Review and Meta-Analysis.

BACKGROUND: Several factors have been identified as being associated with increased adherence to antiretroviral therapy, including sero-status disclosure; however, studies examining the effect of disclosure on ART adherence in Ethiopia have had inconsistent findings. This systematic review and meta-analysis therefore aims to estimate the pooled effect of disclosure on adherence to ART among adults living with HIV in Ethiopia. METHODS: We performed a systematic search for articles reporting on peer-reviewed, quantitative, English-language observational studies of reporting the association between self sero-status disclosure and good ART adherence in adults living with HIV/AIDS in Ethiopia during published from 2010 to 2015. We searched four electronic databases: PubMed/Medline, the World Health Organization\u27s Hinari portal (which includes the SCOPUS, African Index Medicus, and African Journals Online databases) for studies from December 1, 2017 to January 30, 2018. We also searched university repositories and conference abstracts for unpublished studies. We conducted a meta-analysis for the pooled effect of adherence using a random effects model in Stata version 14 and assessed publication bias using the Egger\u27s test for funnel plot asymmetry. RESULTS: Our search returned in 179 studies, of which seven (3.9%), were eligible and included in the final meta-analysis. The seven included studies were conducted from 2010 to 2015. Our analysis found that disclosure had a significant effect on the adherence to ART in adult patients living with HIV. Patients who disclosed were 1.64 times more likely to have good adherence to ART compared with those who did not (OR: 1.64, 95% CI: 1.11, 2.42). The small number of studies eligible for review and differences in study definitions of adherence and disclosure were the main limitations of this study. CONCLUSION: This review found a statistically significant positive effect of disclosure status on the adherence to ART in adult patients living with HIV in Ethiopia. This suggests that Ethiopia\u27s national treatment and prevention programs should redouble efforts to encourage self-disclosure among people living with HIV/AIDS. Encouraging supportive social environments for disclosure, and promoting partner notification and partner disclosure support initiatives might be particularly helpful in this regard

A global view of Pc3 wave activity in near-Earth space : Results from hybrid-Vlasov simulations

Ultra-low frequency (ULF) waves in the Pc3 range, with periods between 10-45 s, are routinely observed in Earth's dayside magnetosphere. They are thought to originate in the foreshock, which extends upstream of the quasi-parallel bow shock and is populated with shock-reflected particles. The foreshock is permeated with ULF waves generated by ion beam instabilities, most notably the "30-s " waves whose periods match those of the Pc3 waves and which are carried earthward by the solar wind flow. However, the global picture of Pc3 wave activity from the foreshock to the magnetosphere and its response to changing solar wind conditions is still poorly understood. In this study, we investigate the global distribution and properties of Pc3 waves across near-Earth space using global simulations performed with the hybrid-Vlasov model Vlasiator. The simulations enable us to study the waves in their global context, and compare their properties in the foreshock, magnetosheath and dayside magnetosphere, for different sets of upstream solar wind conditions. We find that in all three regions the Pc3 wave power peaks at higher frequencies when the interplanetary magnetic field (IMF) strength is larger, consistent with previous studies. The Pc3 wave power is significantly enhanced in all three regions for higher solar wind Alfven Mach number. As this parameter is known to affect the shock properties but has little impact inside the magnetosphere, this brings further support to the magnetospheric waves originating in the foreshock. Other parameters that are found to influence the foreshock wave power are the solar wind density and the IMF cone angle. Inside the magnetosphere, the wave power distribution depends strongly on the IMF orientation, which controls the foreshock position upstream of the bow shock. The wave power is largest when the angle between the IMF and the Sun-Earth line is smallest, suggesting that wave generation and transmission are most efficient in these conditions.Peer reviewe