377 research outputs found
Genome-Wide snp analysis of southern african populations provides new insights into the dispersal of bantu-Speaking groups
The expansion of Bantu-speaking agropastoralist populations had a great impact on the genetic, linguistic, and cultural variation of sub-Saharan Africa. It isgenerally accepted that Bantulanguages originated inanarea around thepresent borderbetweenCameroon and Nigeria approximately 5,000 years ago, from where they spread South and East becoming the largest African linguistic branch. The demic consequences of this event are reflected in the relatively high genetic homogeneity observed acrossmost of sub-Saharan Africapopulations. Inthiswork, weexploredgenome-wide singlenucleotidepolymorphismdata from28populations to characterize the genetic components present in sub-Saharan African populations. Combining novel data from four SouthernAfrican populations withpreviouslypublishedresults,we reject the hypothesis that the" non-Bantu" geneticcomponent reported inSouth-Eastern Africa (Mozambique) reflects extensive gene flow between incoming agriculturalist and resident hunter-gatherer communities.We alternatively suggest that this novel component is the result of demographic dynamics associated with the Bantu dispersal
Integrating Air-related Health Surveillance into Air Quality Management: Perceptions and Practicalities
Health surveillance is presently not an integral part of air quality management in South Africa, although ambient air pollution standards are derived from health effects of personal exposure. In a survey to air quality officials and environmental health practitioners (n = 361 ), respondents were asked to comment on a discussion document regarding ways to put health onto the air quality management agenda. Less than 7% of the sample (n = 23) responded, the most likely reasons being: overloaded staff; lack of knowledge about air quality-related health; and apathy. All respondents acknowledged their support of the concepts, one suggested inclusion of PM25 and airspora over and above criteria pollutants, and one mentioned use of an indicator 'number of complaints of visual air pollution and odour'. In general, it would appear that the links between air quality and health risks are not well understood and, more importantly, assessing airrelated health outcomes with respect to air quality is not a part of Local Municipalities' Integrated Development Plans. To motivate for necessary changes in Health Information Systems and data management, evidence of valuable application is required. Without readily available health facility and local municipality-specific data on respiratory and cardiovascular illnesses, it will prove difficult to track whether implemented air pollution mitigation measures will have positive health impacts
Systems thinking: A turning point for improving respectful obstetric care in South African health districts
Poorly functioning health systems and local health systems barriers affect many women giving birth in low- and middle-income countries. The district clinical specialist teams in South Africa are uniquely positioned to provide facilitation and mentoring during interventions for improving the weak primary healthcare system. To ensure success, four key principles should be considered during scale-up of interventions: systems thinking and awareness of contexts and barriers; a focus on sustainability; harnessing factors known to enhance scalability; and respect for human rights and equity. Asking the right questions about the responsibilities of health systems at the micro-, meso- and macro-levels will benefit scale-up processes and sustain innovative pathways to high-quality obstetric care in communities
Graduate Unemployment in the Face of Skills Shortages: A Labour Market Paradox
Analysts agree that South Africa's unemployment is structural in the sense that the unemployed generally possess lower skills than what is required by the economy. In the context of increasing demand for skilled workers due to technological changes and the need to become globally more competitive, graduates would be expected to find employment without difficulty. However, against expectations unemployment has been increasing among young people with tertiary qualifications since 1995. This paper investigates the nature of this phenomenon. Evidence suggests that learners are inadequately prepared for both tertiary studies and entry into the labour market. Lack of, or inadequate career guidance means that they do not choose fields of study and types of qualifications with good employment prospects. In addition, lack of soft skills and workplace experience mean that employers are reluctant to employ graduates, preferring more experienced people instead
Molecular identification of different Theileria and Babesia species infecting sheep in Sudan
The epidemiological aspects of sheep piroplasmosis in Sudan are poorly studied, and further
investigations using sensitive and precise techniques are required. In this study, the Reverse Line Blot (RLB)
hybridization assay was used to detect and simultaneously differentiate between Theileria and Babesia species. DNA
was extracted from blood collected on filter paper (n=219) from apparently healthy sheep from six different
geographical localities in Sudan. Results indicated that Theileria ovis (88.6%), T. separata (20.1%), T. lestoquardi
(16.4%) and T. annulata (16.4%) DNA could be detected in the blood samples. Single and mixed Theileria infections
were detected in 74 (33.8%) and 124 (56.6%) respectively and T. ovis being the most prevalent species in the country.
T. ovis and T. separata were reported for the first time in sheep in Sudan.University of Elimam Elmahadi, Ministry of High Education and Scientific Research, Sudanhttp://www.bioone.org/loi/copaam2016Veterinary Tropical Disease
Bone remodeling in the longest living rodent, the naked mole-rat : interelement variation and the effects of reproduction
The pattern of bone remodeling of one of the most peculiar mammals in the world, the naked mole-rat (NMR), was assessed. NMRs are known for their long lifespans among rodents and for having low metabolic rates. We assessed long-term in vivo bone labeling of subordinate individuals, as well as the patterns of bone resorption and bone remodeling in a large sample including reproductive and non-reproductive individuals (n = 70). Over 268 undecalcified thin cross-sections from the midshaft of humerus, ulna, femur and tibia were analyzed with confocal fluorescence and polarized light microscopy. Fluorochrome analysis revealed low osteogenesis, scarce bone resorption and infrequent formation of secondary osteons (Haversian systems) (i.e., slow bone turnover), thus most likely reflecting the low metabolic rates of this species. Secondary osteons occurred regardless of reproductive status. However, considerable differences in the degree of bone remodeling were found between breeders and non-breeders. Pre-reproductive stages (subordinates) exhibited quite stable skeletal homeostasis and bone structure, although the attainment of sexual maturity and beginning of reproductive cycles in female breeders triggered a series of anabolic and catabolic processes that up-regulate bone turnover, most likely associated with the increased metabolic rates of reproduction. Furthermore, bone remodeling was more frequently found in stylopodial elements compared to zeugopodial elements. Despite the limited bone remodeling observed in NMRs, the variation in the pattern of skeletal homeostasis (interelement variation) reported here represents an important aspect to understand the skeletal dynamics of a small mammal with low metabolic rates. Given the relevance of the remodeling process among mammals, this study also permitted the comparison of such process with the well-documented histomorphology of extinct therapsids (i.e., mammalian precursors), thus evidencing that bone remodeling and its endocortical compartmentalization represent ancestral features among the lineage that gave rise to mammals. It is concluded that other factors associated with development (and not uniquely related to biomechanical loading) can also have an important role in the development of bone remodeling.CONICYT; National Research Foundation and DST-NRF.http://www.wileyonlinelibrary.com/journal/joahj2022Mammal Research InstituteZoology and Entomolog
Energetics and water flux in the subterranean rodent family Bathyergidae
The doubly labeled water (DLW) technique and indirect calorimetry enable measurement
of an animal’s daily energy expenditure (DEE, kJ/day), resting metabolic rate (RMR,
kJ/d), sustained metabolic scope (SusMS), body fat content (BF, %) as well as water
turnover (WTO, ml/day), and water economy index (ml/kJ). Small mammals have been
the primary focus of many of the DLW studies to date. From large multi-species analyses
of the energetics and water flux of aboveground small mammals, well-defined trends
have been observed. These trends mainly refer to an adaptive advantage for lower
RMR, DEE, SusMS, WTO and WEI in more ariddwelling animals to increase water
and energy savings under low and unpredictable resource availability. The study of
the subterranean rodent family Bathyergidae (African mole-rats) has been of particular
interest with regards to field metabolic rate and metabolic studies. Although a great deal
of research has been conducted on the Bathyergidae, a complete overview and multispecies analysis of the energetics and water flux of this family is lacking. Consequently,
we assessed DEE, RMR, SusMS, BF, WTO and WEI across several different species
of bathyergids from various climatic regions, and compared these to the established
patterns of energetics and water flux for aboveground rodents. There was notable
variation across the Bathyergidae inhabiting areas with different aridities, often contrary
to the variations observed in above-ground species. These include increased DEE and
WEI in arid-dwelling bathyergid species. While the climate was not a clear factor when
predicting the SusMS of a bathyergid species, rather the degree of group living was a
strong driver of SusMS, with solitary species possessing the highest SusMS compared
to the socially living species. We conclude that the constraints of the underground
lifestyle and the consequent spectrum of social behaviors possessed by the family
Bathyergidae are most likely to be more crucial to their energetics and water flux than
their habitat; however other important unstudied factors may still be at play. More so,
this study provides evidence that often unreported parameters, measured through use
of the DLW technique (such as BF and WEI) can enable species to be identified that
might be at particular risk to climate change.The SARChI Chair of Mammal Behavioral
Ecology and Physiology, National Research
Foundation RSA, the British
Ecological Society (SEPG), and the National Science Foundation,
United States.http://frontiersin.org/Ecology_and_Evolutiondm2022Zoology and Entomolog
Molecular detection and characterisation of protozoan and rickettsial pathogens in ticks from cattle in the pastoral area of Karamoja, Uganda
Ticks and tick-borne diseases (TBDs) significantly affect cattle production and the livelihoods of communities in pastoralist areas. Data on protozoan and rickettsial pathogens in ticks infesting cattle in Uganda is scanty; while it is an indicator of the likelihood of disease transmission and occurrence. A cross-sectional study was conducted amongst cattle in the Karamoja Region, northeastern Uganda, from July through September 2017, to determine the tick species diversity, identify protozoan and rickettsial pathogens in the ticks, and characterise pathogenic species by sequence and phylogenetic analyses. About 50 % of the ticks detected from each predilection site on each animal were collected from 100 purposively-selected cattle from 20 randomly-selected herds. Twelve tick species belonging to the genera Amblyomma, Rhipicephalus and Hyalomma were identified, the most abundant being Amblyomma lepidum (93.9 %), followed by Amblyomma variegatum (2.0 %) and Rhipicephalus evertsi evertsi (1.0 %). Tick species that have not been reported in recent studies amongst cattle in Uganda were found, namely Rhipicephalus pravus, Rhipicephalus praetextatus and Rhipicephalus turanicus. The ticks were grouped into 40 pools, by species and location, and the reverse line blot (RLB) hybridisation assay was used to detect pathogens from the ticks. The most frequently detected tick-borne parasites were Theileria mutans, Theileria velifera and Theileria parva, each observed in 25 % (10/40) of the tick pools. Tick-borne pathogens, namely Babesia rossi, Babesia microti and Theileria sp. (sable) that are not common to, or not known to infect, cattle were identified from ticks. The gene encoding Ehrlichia ruminantium pCS20 region, the Ehrlichia and Anaplasma 16S rRNA gene, and T. parva p67 sporozoite antigen gene were amplified, cloned and sequenced. Seven novel E. ruminantium pCS20 variants were identified, and these grouped into two separate clusters with sequences from other parts of Africa and Asia. The T. parva p67 sequences were of the allele type 1, and parasites possessing this allele type are commonly associated with East Coast fever in eastern Africa. Analysis of the Ehrlichia and Anaplasma 16S rRNA gene sequences showed that they were closely related to Rickettsia africae and to a new Ehrlichia species variant recently found in China. Our R. africae 16S rRNA sequences grouped with R. africae isolates from Nigeria, Egypt and Benin. The information on tick species diversity and pathogens in the various tick species provides an indicator of potential transmission amongst cattle populations, and to humans, and can be useful to estimate disease risk and in control strategies.The Directorate-General for Development Cooperation (DGDC) through the Institute of Tropical Medicine (ITM) in Antwerp, Belgium (Flanders), the University of Pretoria, South Africa and the Claude Leon Foundation, South Africa.https://www.elsevier.com/locate/ttbdishj2022Veterinary Tropical Disease
Sleep and wake in rhythmic vs arrhythmic chronotypes of a microphthalmic species of African mole rat (Cryptomys mechowi)
The giant Zambian molerat (Cryptomys mechowi) is a subterranean African rodent
noted for its regressed visual system and unusual patterns of circadian rhythmicity – within
this species some individuals exhibit distinct regular circadian patterns while others have
arrhythmic circadian patterns. The current study was aimed at understanding whether
differences in circadian chronotypes in this species affects the patterns and proportions of the
different phases of the sleep-wake cycle. Physiological parameters of sleep (EEG and EMG)
and behaviour (video recording) were recorded continuously for 72 h from six mole rats
(three rhythmic and three arrhythmic) using a telemetric system and a low light CCTV
camera connected to a DVD recorder. The telemetric data was scored (in both 5 s and 1 min epochs) as wake, nonREM sleep (NREM) and rapid eye movement (REM) stages subject to
the correlation between EEG, EMG and behaviour. Spectral power was calculated for EEG in
each implanted individual, which assisted in understanding the sleep phases and the intensity
of NREM between the chronotypes. In addition REM periodicity was calculated from which
sleep cycle length was inferred. The results indicate that the arrhythmic individuals spend
more time in waking with a longer average duration of a waking episode, less time in NREM
with a shorter average duration of a NREM episode though a greater nonREM sleep intensity,
and similar sleep cycle lengths. The time spent in REM and the average duration of a REM
episode was similar between the chronotypes.http://content.karger.com/ProdukteDB/produkte.asp?Aktion=JournalHome&ProduktNr=223831ab201
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