165 research outputs found

    Cloud Studies: The Visible Invisible

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    Clouds have long been objects of fascination, although their taxonomy was only established by early nineteenth-century meteorologists. For aestheticians and art historians, clouds also raise questions about painting's illusionistic uses of space. In John Constable's painting, clouds represent an "organ of sentiment"; his cloud sketches are exercises in representing space, mass, and mood. The poet John Clare also uses clouds to represent states of mind for which he lacked a language. Natural observation in Con­stable and Clare has different valances: for Clare, observation represents a form of defence against impingement; for Constable, "the man of the clouds," the science of cloud-watching gives rise to thought. The material­ity of clouds (bearing dust and pollution) is a feature of nineteenth-century climatic accounts. Merleau-Ponty's phenomenology offers a contemporary theory of clouds as embodied and related seeing. Constable's cloud-sketches suggest that clouds are not just objects, but a form of cognition

    TROPIC: Transactional Resource Orchestration Platform In The Cloud

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    Realizing Infrastructure-as-a-Service (IaaS) cloud requires a control platform to orchestrate cloud resource provisioning, configuration, and decommissioning across a distributed set of diverse physical resources. This orchestration is challenging due to the rapid growth of data centers, high failure rate of commodity hardware and the increasing sophistication of cloud services. This paper presents the design and implementation of TROPIC, a highly available, transactional resource orchestration platform for building IaaS cloud infrastructures. TROPIC’s orchestration procedures that manipulate physical resources are transactional, automatically guaranteeing atomicity, consistency, isolation and durability of cloud operations. Through extensive evaluation of our prototype implementation, we demonstrate that TROPIC can meet production-scale cloud orchestration demands, while maintaining our design goals of safety, robustness, concurrency and high availability

    Plant poisonings in livestock in Brazil and South Africa

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    Information on intoxication of livestock by plants in Brazil, in terms of cause, clinical signs and pathology, is compared with information on livestock poisoning by plants in South Africa. Plant poisoning, including mycotoxicosis, is considered to be one of three major causes of death in livestock in Brazil, which is one of the top beef producing countries in the world, with a cattle population of more than 200 million. Cattle production in South Africa is on a more modest scale, but with some 600 species of plants and fungi known to cause toxicity in livestock, as opposed to some 130 species in Brazil, the risk to livestock in South Africa appears to be much greater. The comparisons discussed in this communication are largely restricted to ruminants.http://www.jsava.co.zaam201

    Communication Strategies for Connecting OneVCU

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    This project analyzes and makes improvement suggestions for communication to VCU faculty and staff. The COVID-19 crisis has brought to light a variety of communication needs. Faculty and staff are feeling overwhelmed by a flood of emails, while at the same time are missing key information. We have assessed the current communication infrastructure, and together with the key VCU communicators have identified improved processes and policies

    Changing ecology of Lake Victoria cichlids and their environment: evidence from C13 and N15 analyses

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    Eutrophication is an increasing global threat to freshwater ecosystems. East Africa’s Lake Victoria has suffered from severe eutrophication in the past decades which is partly responsible for the dramatic decline in haplochromine cichlid species diversity. However, some zooplanktivorous and detritivorous haplochromine species recovered and shifted their diet towards macro invertebrates and fish. We used four formalin preserved cichlid species caught over the past 35 years to investigate whether stable isotopes of these fish are reflecting the dietary changes, habitat differences and if these isotopes can be used as indicators of eutrophication. We found that d15N signatures mainly reflected dietary shifts to larger prey in all four haplochromine species. Shifts in d13C signatures likely represented habitat differences and dietary changes. In addition, a shift to remarkably heavy d13C signatures in 2011 was found for all four species which might infer increased primary production and thus eutrophication although more research is needed to confirm this hypothesis. The observed temporal changes confirm previous findings that preserved specimens can be used to trace historical changes in fish ecology and the aquatic environment. This highlights the need for continued sampling as this information could be of essence for reconstructing and predicting the effects of environmental changes

    Statistical analysis of the effect of varying material and manufacturing conditions on the mechanical properties of high-density polyethylene/layered double hydroxide composites

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    DATA AVAILABILITY STATEMENT : The data that support the findings of this study are openly available in University of Pretoria Research Data Repository (Figshare) at https://DOI.org/10.25403/ UPresearchdata.22126433.v1.Polymers are used in various industrial applications due to their ease of production, light weight, and ductility. Fillers such as clays are added to polymers to improve a range of factors such as material processing, thermal properties, fire retardance and cost. However, adding clays may negatively impact the mechanical performance of the composite. In addition, manufacturing parameters, for example, number of extrusions, press time, and so forth may also have an influence on the resulting composite system. This study performs a statistical analysis on a set of previously obtained experimental results, which investigated the influence of various manufacturing, material, and testing parameters on the composite mechanical properties. Exploratory data and statistical analysis techniques are applied to the historical tensile test data to gain insight into the influence on mechanical properties as well as the relationships and interactions between the parameters. Specifically, it is shown that clay loading does not have a statistically significant effect on the composite mechanical properties, which is contrary to literature. Another surprising result is the poor performance of the clay that is compatible with high-density polyethylene compared to the clay that is compatible with poly vinyl chloride. The contribution of this paper is to demonstrate the usefulness of applying statistical analysis on a large volume of data to understand the diverse correlations between the different variables.http://wileyonlinelibrary.com/journal/pls2am2024Chemical EngineeringMechanical and Aeronautical EngineeringNon

    Regional projections of extreme apparent temperature days in Africa and the related potential risk to human health

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    Regional climate modelling was used to produce high resolution climate projections for Africa, under a “business as usual scenario”, that were translated into potential health impacts utilizing a heat index that relates apparent temperature to health impacts. The continent is projected to see increases in the number of days when health may be adversely affected by increasing maximum apparent temperatures (AT) due to climate change. Additionally, climate projections indicate that the increases in AT results in a moving of days from the less severe to the more severe Symptom Bands. The analysis of the rate of increasing temperatures assisted in identifying areas, such as the East African highlands, where health may be at increasing risk due to both large increases in the absolute number of hot days, and due to the high rate of increase. The projections described here can be used by health stakeholders in Africa to assist in the development of appropriate public health interventions to mitigate the potential health impacts from climate change

    Antibacterial activity of crude extracts of some South African medicinal plants against multidrug resistant etiological agents of diarrhoea

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    Abstract Background This study evaluated the antibacterial activity of some plants used in folklore medicine to treat diarrhoea in the Eastern Cape Province, South Africa. Methods The acetone extracts of Acacia mearnsii De Wild., Aloe arborescens Mill., A. striata Haw., Cyathula uncinulata (Schrad.) Schinz, Eucomis autumnalis (Mill.) Chitt., E. comosa (Houtt.) Wehrh., Hermbstaedtia odorata (Burch. ex Moq.) T.Cooke, Hydnora africana Thunb, Hypoxis latifolia Wight, Pelargonium sidoides DC, Psidium guajava L and Schizocarphus nervosus (Burch.) van der Merwe were screened against Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, multi-resistant Salmonella enterica serovar Isangi, S. typhi, S. enterica serovar Typhimurium, Shigella flexneri type 1b and Sh. sonnei phase II. A qualitative phytochemical screening of the plants extracts was by thin layer chromatography. Plants extracts were screened for antibacterial activity using serial dilution microplate technique and bioautography. Results The TLC fingerprint indicated the presence of terpenoids and flavonoids in the herbs. Most of the tested organisms were sensitive to the crude acetone extracts with minimum inhibitory concentration (MIC) values ranging from 0.018–2.5 mg/mℓ. Extracts of A. striata, C. uncinulata, E. autumnalis and P. guajava were more active against enteropathogens. S. aureus and Sh. flexneri were the most sensitive isolates to the crude extracts but of significance is the antibacterial activity of A. arborescens and P. guajava against a confirmed extended spectrum betalactamase positive S. enterica serovar Typhimurium. Conclusion The presence of bioactive compounds and the antibacterial activity of some of the selected herbs against multidrug resistant enteric agents corroborate assertions by traditional healers on their efficacies

    IDEAL, the Infectious Diseases of East African Livestock project open access database and biobank

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    The Infectious Diseases of East African Livestock (IDEAL) project was a longitudinal cohort study of calf health which was conducted in Western Kenya between 2007–2010. A total of 548 East African shorthorn zebu calves were recruited at birth and followed at least every 5 weeks during the first year of life. Comprehensive clinical and epidemiological data, blood and tissue samples were collected at every visit. These samples were screened for over 100 different pathogens or infectious exposures, using a range of diagnostic methods. This manuscript describes this comprehensive dataset and bio-repository, and how to access it through a single online site (http://data.ctlgh.org/ideal/). This provides extensive filtering and searching capabilities. These data are useful to illustrate outcomes of multiple infections on health, investigate patterns of morbidity and mortality due to parasite infections, and to study genotypic determinants of immunity and disease
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