Estimates of energy fluxes associated with sprites in the mesosphere

We present calibrated estimates of photon flux, lightning peak Poynting flux and Joule heating associated with the brightest region of sprites observed in the mesosphere over South Africa. The sprites' photon fluxes were estimated using 28 sprites events (observed during the 2019 sprites campaign) calibrated by stars in the sprite's image background. The lightning driven background electric field associated with the brightest region of sprites were found to vary from 0.1 to 6.7 E k (local air breakdown field). The lightning return stroke at lower frequencies (4 Hz - 2 kHz) has more influence in carrot sprites than in column sprites formation processes. The lightning peak Poynting flux and Joule heating were estimated from calibrated electromagnetic field measurements made in parallel with eight sprites events (observed during the 2020 sprites campaign). The photon flux, peak Poynting flux, and peak Joule heating associated with the brightest region of sprites were found to be 1.1 × 10 −7 W/m 2, 12.7 W/m 2, and 4.7 × 10 −3 W/m 2 on average, respectively. The altitude/distance-normalised lightning peak Poynting flux decreases with increasing atmospheric altitude. The photon flux from column sprites decreased with increased altitude of the brightest region. Column sprites have a shorter time delay (<30 ms) from their parent lightning strokes than carrot sprites (up to 145 ms)

Low levels of physical activity in female adolescents cause overweight and obesity: Are our schools failing our children?

The increasing prevalence of overweight and obesity among female adolescents is a global health problem. In developing countries such as South Africa, this increase is often associated with urbanisation and the adoption of a Western lifestyle. Two aspects of the Western lifestyle that contribute to the development of overweight and obesity are a decrease in physical activity levels and an increase in the consumption of energy-dense food, high in fats and refined sugar. Information on the prevalence of increased body fatness in populations in transition is scarce, but necessary for effective planning and intervention. Current indications are that there is a trend towards unhealthy behaviour among high-school girls, globally and in South Africa. Schools can play an important role in the prevention of overweight and obesity among schoolgirls. It is recommended that school governing bodies institute remedial action to prevent weight gain in children, especially girls

Self-report measurement of pain & symptoms in palliative care patients: a comparison of verbal, visual and hand scoring methods in Sub-Saharan Africa

Background: Despite a high incidence of life-limiting disease, there is a deficit of palliative care outcome evidence in sub-Saharan Africa. Providers of end of life care call for appropriate measurement tools. The objective is to compare four approaches to self-report pain and symptom measurement among African palliative care patients completing the African Palliative Care Association African Palliative Outcome Scale (APCA African POS). Methods: Patients were recruited from five services (4 in South Africa and 1 in Uganda). Research nurses cross-sectionally administered POS pain and symptom items in local languages. Both questions were scored from 0 to 5 using 4 methods: verbal rating, demonstrating the score using the hand (H), selecting a face on a visual scale (F), and indicating a point on the Jerrycan visual scale (J). H, F and J scores were correlated with verbal scores as reference using Spearman’s rank and weighted Kappa. A Receiver Operating Characteristic (ROC) analysis was performed. Results: 315 patients participated (mean age 43.5 years, 69.8% female), 71.1% were HIV positive and 35.6% had cancer, 49.2% lived in rural areas. Spearman’s rank correlations for pain scores were: H: 0.879, F: 0.823, J: 0.728 (all p  F > J (0.96–0.89) in ROC analysis. Conclusions: Hands and faces scoring methods correlate highly with verbal scoring. The Jerrycan method had only moderate weighted Kappa. POS scores can be reliably measured using hand or face score

AVONET: morphological, ecological and geographical data for all birds

Functional traits offer a rich quantitative framework for developing and testing theories in evolutionary biology, ecology and ecosystem science. However, the potential of functional traits to drive theoretical advances and refine models of global change can only be fully realised when species‐level information is complete. Here we present the AVONET dataset containing comprehensive functional trait data for all birds, including six ecological variables, 11 continuous morphological traits, and information on range size and location. Raw morphological measurements are presented from 90,020 individuals of 11,009 extant bird species sampled from 181 countries. These data are also summarised as species averages in three taxonomic formats, allowing integration with a global phylogeny, geographical range maps, IUCN Red List data and the eBird citizen science database. The AVONET dataset provides the most detailed picture of continuous trait variation for any major radiation of organisms, offering a global template for testing hypotheses and exploring the evolutionary origins, structure and functioning of biodiversity

Estimates of energy fluxes associated with sprites in the mesosphere

We present calibrated estimates of photon flux, lightning peak Poynting flux and Joule heating associated with the brightest region of sprites observed in the mesosphere over South Africa. The sprites' photon fluxes were estimated using 28 sprites events (observed during the 2019 sprites campaign) calibrated by stars in the sprite's image background. The lightning driven background electric field associated with the brightest region of sprites were found to vary from 0.1 to 6.7 Ek (local air breakdown field). The lightning return stroke at lower frequencies (4 Hz - 2 kHz) has more influence in carrot sprites than in column sprites formation processes. The lightning peak Poynting flux and Joule heating were estimated from calibrated electromagnetic field measurements made in parallel with eight sprites events (observed during the 2020 sprites campaign). The photon flux, peak Poynting flux, and peak Joule heating associated with the brightest region of sprites were found to be 1.1 × 10−7 W/m2, 12.7 W/m2, and 4.7 × 10−3 W/m2 on average, respectively. The altitude/distance-normalised lightning peak Poynting flux decreases with increasing atmospheric altitude. The photon flux from column sprites decreased with increased altitude of the brightest region. Column sprites have a shorter time delay (&lt;30 ms) from their parent lightning strokes than carrot sprites (up to 145 ms).</p

3D triangulation of Transient Luminous Events over Africa

We present the first 3D triangulation of Transient Luminous Events (TLEs) over Africa. The 6 TLEs were simultaneously observed in the middle atmosphere from Sutherland and Carnarvon in South Africa, separated by 192 km, during the 2019 sprites campaign. These two distinctive locations have low radio interference and are free from light pollution. The lightning times, locations, peak current, and polarities, which initiated the observed TLEs, were obtained from the South African Lightning Detection Network and Earth Networks Total Lightning Networks. We investigate the TLEs' altitude and horizontal displacement from their parent lightning strokes. TLEs appear approximately 12.5 to 49.3 km away from their parent lightning strokes. We found that TLE altitudes range from 29 to 92.6 km. The lightning electric field and peak current may be related to the displacement of TLEs and the TLEs' horizontal spread

Lightning parameters of sprites and diameter of halos over South Africa

Transient Luminous Events (TLEs) above thunderclouds have been previously associated with variables such as the lightning Charge Moment Change (CMC), charge height, charge transfer, and lightning current rise-time. We show for the first time a comparison of the CMC, rise-time, fall-time, peak electric field, and peak current of the lightning discharges associated with 11 column, 11 carrot, and 18 sprites with halo. We found that carrot sprites are induced by a lightning discharge with CMC, peak electric field, and peak current greater and less than that for column sprites and sprites with halo, respectively. Sprites with a halo are initiated by a lightning discharge with a longer rise-time and fall-time than that for column and carrot sprites. Column sprites top altitude and carrot sprites brightest region altitude positively correlate with lightning rise-time. For carrot sprites top altitude, the results suggest that the electrical breakdown region decreases in altitude for a longer fall-time, greater peak electric field, and greater peak current. For the altitude of the sprites brightest region, column sprites correlate negatively with lightning fall-time, peak electric field, and CMC, and column sprites top altitude also correlates negatively with lightning peak electric field. For sprites with a halo top altitude increased with lightning fall-time and peak current, and sprites with a halo brightest altitude increased with an increase in lightning CMC. Halo diameters correlate positively with lightning fall-time, peak electric field, and peak current. The investigated lightning parameters can be used to identify the initiated sprites morphological type when optics are not available

Morphological variation in the Sabota Lark Calendulauda sabota in southern Africa

Separation of the eight southern African subspecies of Sabota Lark Calendulauda sabota into thick-billed and slender-billed groups has been proposed. This study used biometric data obtained from museum skins in South Africa to evaluate  morphological variation in the subspecies as a basis for the delineation of Sabota Lark into the thick-billed, slender-billed and intermediate groups. Six mensural characters were measured by a single researcher. Box plots were used to identify outliers, the 75% rule for diagnostics was applied to determine whether subspecies were distinct, and discriminant function analysis was used to evaluate the validity of the thick- and slender-billed groups, and the existence of a putative intermediate group. The results of this study support the separation of Sabota Lark into slender-billed (C.s. sabota, C.s. sabotoides, C.s. suffusca and C.s. waibeli) and thick-billed (C.s. bradfieldi, C.s. herero and C.s. naevi) groups based on culmen-nare length and bill width. The results failed to provide evidence for an intermediate group. Some C.s. ansorgei specimens had thick-billed characteristics, whereas others had slender-billed characteristics, implying sympatry of the thick- and slender-billed groups in southern Angola and north-western Namibia.Keywords: 75% rule for diagnostics, Alaudidae, biometric data, delineating subspecies, discriminant function analysis, geographic variatio