75 research outputs found
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<i>Aloe succotrina</i> (Asphodelaceae)
Aloe succotrina has a very long and complex taxonomic and nomenclatural history with wrong synonymy that is rivalled by few other aloes. This is mostly due to early authors wrongly assuming that this plant is from the Island of Socotra (Reynolds 1950). It has been in cultivation in Europe for over three hundred years, so consequently it is rather surprising that this iconic fynbos species has not featured in this journal until now
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<i>Kalanchoe beharensis</i>. Crassulaceae: Kalanchooideae
Kalanchoe beharensis is one of the largest species of the diverse genus, reaching a height of about 3 m, one of only a few that can be regarded as truly arborescent. The species is discussed in detail in terms of its history, taxonomy, relationships, distribution, habitat, variability and cultivation. It is described in full and illustrated with a water-colour painting and colour photos. This species is endemic to and fairly widespread in western, central and eastern Madagascar including Behara after which it is named. It has been introduced to several mild-climate parts of the world and is now widespread in cultivation
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Aloiampelos ciliaris var. ciliaris. Asphodelaceae: Alooideae
Aloiampelos ciliaris is the type of a new genus of just seven species separated from Aloe in 2013 to accommodate the scrambling South African aloes. The history, taxonomy, distribution, ecology, cytology and cultivation of this species are all discussed in detail. This species is unique for Southern Africa in having a hexaploid chromosome count of 2n=42. The leaf structure is also distinctive with an amplexicaul base bearing conspicuous white cilia. It is endemic to the Eastern Cape Province
Spider silk protein structure analysis by FTIR and STXM spectromicroscopy techniques
Spider silk displays incredible strength and elas¬ticity for its size and weight.[1] These properties have sparked interest in determining the protein structures of the silk fibers allowing for the pro¬duction of synthetic silks.[2] This study compares the mid-infrared (Mid IR) spectra of silk from five different spider species to investigate the com-monalities between species and web type. The results demonstrate the Mid IR spectra from all types of spider silk to be similar, showing protein peaks in the Amide I and II regions. To study the environmental effects of the acid solution on the silk protein structure, two of the five species’ silk: Black & Yellow Orb Weaver (Argiope aurantia) and Black Widow (Latrodectus hesperus), were exposed to either rain water or 0.001 M sulphuric acid solution, similar to acid rain in pH. Spectra obtained at the Mid IR beamline and the data obtained from the X-ray Absorption Near Edge Spectroscopy (XANES) were compared for these samples to see the effect of the acid rain-like solu¬tion on the silk proteins. No conclusive evidence from the data is present to suggest that the acid rain solution had an effect on the protein structures of either type of spider silk.La soie d’araignée est à la fois robuste et flexible pour sa taille et son poids.[1] Ces propriétés ont piqué la curiosité de déterminer la structure des protéines des fibres de soie qui pourrait permettre éventuelle¬ment la production des soies synthétiques.[2] Cette étude compare les spectres mi- infrarouges (Mi IR) de soie de cinq espèces différentes d’araignée afin de trouver des similitudes entre les espèces et les genres de toiles. Les résultats démontrent que les spectres mi- infrarouges de tout type de soie d’araignée étudié sont similaires, présentant des apogées de protéines dans les régions de l’Amide I et II. Afin d’étudier les effets environnementaux d’une solution acide sur la structure de la proté¬ine de soie, la soie de deux des cinq espèces, le orbe tisserand noir et jaune (Argiope aurantia) et la veuve noire (Latrodectus Hesperus), ont été expo¬sé soit à la pluie naturelle soit à une solution d’acide sulfurique 0.001 M qui est proche au pH de la pluie acide. Les spectres obtenus à l’onde dirigée Mi IR et les données obtenues de l’absorption de la radi¬ographie près du seuil de la spectroscopie (ARSS) ont été comparés de ces échantillons afin de con¬stater l’effet de la solution d’acide sulfurique sur des protéines de soie. Il n’y avait aucune preuve probante des données suggérant que la solution d’acide sulfurique avait un effet sur la structure des protéines de soie des araignées étudié
'Family comes in all forms, blood or not': disrupting dominant narratives around the patriarchal nuclear family
After nearly 25 years of democracy, lives of young South Africans are
still profoundly shaped by the legacies of apartheid. This paper
considers how these differences are produced, maintained and
disrupted through an exploration of changing narratives
developed by a small group of South African pre-service teachers,
with a particular focus on the narratives developed around
discourses of fatherhood generally and absent fathers in
particular. We draw on interviews conducted with three students
in which we discussed their digital stories and literature reviews.
In this paper, we draw attention to the limitations of digital
storytelling and the risks such autobiographical storytelling
presents of perpetuating dominant narratives that maintain and
reproduce historical inequalities. At the same time, in highlighting
ways in which this risk might be confronted, the paper also aims
to show the possibilities in which these dominant narratives may
be challenged.IBS
Discovery of new colonies by Sentinel2 reveals good and bad news for emperor
The distribution of emperor penguins is circumpolar, with 54 colony locations currently reported of which 50 are currently extant as of 2019. Here we report on eight newly discovered colonies and confirm the rediscovery of three breeding sites, only previously reported in the era before Very High Resolution satellite imagery was available, making a total of 61 breeding locations. This represents an increase of ~20% in the number of breeding sites, but, as most of the colonies appear to be small, they may only increase the total population by around 5–10%. The discoveries have been facilitated by the use of Sentinel2 satellite imagery, which has a higher resolution and more efficient search mechanism than the Landsat data previously used to search for colonies. The small size of these new colonies indicates that considerations of reproductive output in relation to metabolic rate during huddling is likely to be of interest. Some of the colonies exist in offshore habitats, something not previously reported for emperor penguins. Comparison with recent modelling results show that the geographic locations of all the newly found colonies are in areas likely to be highly vulnerable under business‐as‐usual greenhouse gas emissions scenarios, suggesting that population decreases for the species will be greater than previously thought
Serological profile of foot-and-mouth disease in wildlife populations of West and Central Africa with special reference to Syncerus caffer subspecies
The role which West and Central African wildlife populations might play in the transmission dynamics of FMD is not known nor have studies been performed in order to assess the distribution and prevalence of FMD in wild animal species inhabiting those specific regions of Africa. This study reports the FMD serological profile extracted from samples (n = 696) collected from wildlife of West and Central Africa between 1999 and 2003. An overall prevalence of FMDV NSP reactive sera of 31.0% (216/696) was estimated, where a significant difference in seropositivity (p = 0.000) was reported for buffalo (64.8%) as opposed to other wild animal species tested (17.8%). Different levels of exposure to the FMDV resulted for each of the buffalo subspecies sampled (p = 0.031): 68.4%, 50.0% and 0% for Nile Buffalo, West African Buffalo and African Forest Buffalo, respectively. The characterisation of the FMDV serotypes tested for buffalo found presence of antibodies against all the six FMDV serotypes tested, although high estimates for type O and SAT 3 were reported for Central Africa. Different patterns of reaction to the six FMDV serotypes tested were recorded, from sera only positive for a single serotype to multiple reactivities. The results confirmed that FMDV circulates in wild ruminants populating both West and Central Africa rangelands and in particular in buffalo, also suggesting that multiple FMDV serotypes might be involved with type O, SAT 2 and SAT 1 being dominant. Differences in serotype and spill-over risk between wildlife and livestock likely reflect regional geography, historical circulation and differing trade and livestock systems
Reconstruction of the Transmission History of RNA Virus Outbreaks Using Full Genome Sequences: Foot-and-Mouth Disease Virus in Bulgaria in 2011
<div><p>Improvements to sequencing protocols and the development of computational phylogenetics have opened up opportunities to study the rapid evolution of RNA viruses in real time. In practical terms, these results can be combined with field data in order to reconstruct spatiotemporal scenarios that describe the origin and transmission pathways of viruses during an epidemic. In the case of notifiable diseases, such as foot-and-mouth disease (FMD), these analyses provide important insights into the epidemiology of field outbreaks that can support disease control programmes. This study reconstructs the origin and transmission history of the FMD outbreaks which occurred during 2011 in Burgas Province, Bulgaria, a country that had been previously FMD-free-without-vaccination since 1996. Nineteen full genome sequences (FGS) of FMD virus (FMDV) were generated and analysed, including eight representative viruses from all of the virus-positive outbreaks of the disease in the country and 11 closely-related contemporary viruses from countries in the region where FMD is endemic (Turkey and Israel). All Bulgarian sequences shared a single putative common ancestor which was closely related to the index case identified in wild boar. The closest relative from outside of Bulgaria was a FMDV collected during 2010 in Bursa (Anatolia, Turkey). Within Bulgaria, two discrete genetic clusters were detected that corresponded to two episodes of outbreaks that occurred during January and March-April 2011. The number of nucleotide substitutions that were present between, and within, these separate clusters provided evidence that undetected FMDV infection had occurred. These conclusions are supported by laboratory data that subsequently identified three additional FMDV-infected livestock premises by serosurveillance, as well as a number of antibody positive wild boar on both sides of the border with Turkish Thrace. This study highlights how FGS analysis can be used as an effective on-the-spot tool to support and help direct epidemiological investigations of field outbreaks.</p> </div
Altered Error Processing following Vascular Thalamic Damage: Evidence from an Antisaccade Task
Event-related potentials (ERP) research has identified a negative deflection within about 100 to 150 ms after an erroneous response – the error-related negativity (ERN) - as a correlate of awareness-independent error processing. The short latency suggests an internal error monitoring system acting rapidly based on central information such as an efference copy signal. Studies on monkeys and humans have identified the thalamus as an important relay station for efference copy signals of ongoing saccades. The present study investigated error processing on an antisaccade task with ERPs in six patients with focal vascular damage to the thalamus and 28 control subjects. ERN amplitudes were significantly reduced in the patients, with the strongest ERN attenuation being observed in two patients with right mediodorsal and ventrolateral and bilateral ventrolateral damage, respectively. Although the number of errors was significantly higher in the thalamic lesion patients, the degree of ERN attenuation did not correlate with the error rate in the patients. The present data underline the role of the thalamus for the online monitoring of saccadic eye movements, albeit not providing unequivocal evidence in favour of an exclusive role of a particular thalamic site being involved in performance monitoring. By relaying saccade-related efference copy signals, the thalamus appears to enable fast error processing. Furthermore early error processing based on internal information may contribute to error awareness which was reduced in the patients
Frontal Non-Invasive Neurostimulation Modulates Antisaccade Preparation in Non-Human Primates
A combination of oculometric measurements, invasive electrophysiological recordings and microstimulation have proven instrumental to study the role of the Frontal Eye Field (FEF) in saccadic activity. We hereby gauged the ability of a non-invasive neurostimulation technology, Transcranial Magnetic Stimulation (TMS), to causally interfere with frontal activity in two macaque rhesus monkeys trained to perform a saccadic antisaccade task. We show that online single pulse TMS significantly modulated antisaccade latencies. Such effects proved dependent on TMS site (effects on FEF but not on an actively stimulated control site), TMS modality (present under active but not sham TMS on the FEF area), TMS intensity (intensities of at least 40% of the TMS machine maximal output required), TMS timing (more robust for pulses delivered at 150 ms than at 100 post target onset) and visual hemifield (relative latency decreases mainly for ipsilateral AS). Our results demonstrate the feasibility of using TMS to causally modulate antisaccade-associated computations in the non-human primate brain and support the use of this approach in monkeys to study brain function and its non-invasive neuromodulation for exploratory and therapeutic purposes
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